CATALYSTS FOR SELECTIVE NITROGEN OXIDE REDUCTION AND ITS MANUFACTURING METHOD

Abstract

Embodiments relate to a metal vanadate catalyst for nitrogen oxide reduction functionalized with H.sub.3-APO.sub.4.sup.A (A=1, 2, or 3) and SO.sub.B.sup.2 (B=3 or 4) and a synthesis method thereof, and more particularly, to a solid-state catalyst for nitrogen oxide reduction, including a transition metal vanadate or a rare-earth metal vanadate as a catalytic site in a support, some of the catalytic sites being modified with H.sub.3-APO.sub.4.sup.A and SO.sub.B.sup.2 functional groups, and a synthesis method thereof.

Claims

1. A catalyst for nitrogen oxide reduction, comprising: a catalyst site including one or more represented by Chemical Formulas 1 to 3 below; and a support on which the catalyst site is supported; wherein the catalyst site is functionalized with H.sub.3-APO.sub.4.sup.A (A=1, 2, or 3) and SO.sub.B.sup.2 (B=3 or 4): [Chemical Formula 1] (TM).sub.XV.sub.2O.sub.X+5 (X is 1, 2, or 3; TM is one or more selected from the group consisting of Mn, Co, Ni, and Cu) [Chemical Formula 2] (RM)VO.sub.4 (RM is one or more selected from the group consisting of La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, and Lu) ##STR00007##

2. The catalyst for nitrogen oxide reduction of claim 1, further including a promoter site, which is an oxide of a Group 15 or 16 element, on the support.

3. The catalyst for nitrogen oxide reduction of claim 2, wherein the promotor site is included in an amount of 10.sup.5% by weight to 50% by weight based on the support.

4. The catalyst for nitrogen oxide reduction of claim 2, wherein the Group 15 or 16 element is included in a combination of one or more of nitrogen (N), phosphorus (P), sulfur (S), arsenic (As), selenium (Se), antimony (Sb), tellurium (Te), bismuth (Bi), polonium (Po), moscovium (Mc), and livermorium (Lv).

5. The catalyst for nitrogen oxide reduction of claim 1, wherein the support includes one of carbon (C), Al.sub.2O.sub.3, MgO, ZrO.sub.2, CeO.sub.2, TiO.sub.2, and SiO.sub.2.

6. The catalyst for nitrogen oxide reduction of claim 1, wherein the transition metal vanadate or rare-earth metal vanadate represented by one or more of the Chemical Formulas 1 to 3 is each included in an amount of 10.sup.5% by weight to 50% by weight based on 100% by weight of the support.

7. The catalyst for nitrogen oxide reduction of claim 1, wherein the support has a porous structure.

8. The catalyst for nitrogen oxide reduction of claim 1, wherein the catalytic site is a vanadate composed of Ni, V, and O; an M/V molar ratio is 0.5 or more and 1.5 or less; a P/(Sb+M+V) molar ratio is 10.sup.2 or more and 1.0 or less; and a S/(Sb+M+V) molar ratio is 10.sup.2 or more and 1.0 or less, and the M is Ni.

9. The catalyst for nitrogen oxide reduction of claim 1, wherein the catalytic site is a vanadate composed of Mn, V, and O; an M/V molar ratio is 0.5 or more and 1.5 or less; a P/(Sb+M+V) molar ratio is 10.sup.2 or more and 1.0 or less; and an S/(Sb+M+V) molar ratio is 10.sup.2 or more and 1.0 or less, and the M is Mn.

10. The catalyst for nitrogen oxide reduction of claim 1, wherein the catalytic site is a vanadate composed of Co, V, and O; an M/V molar ratio is 0.5 or more and 1.5 or less; a P/(Sb+M+V) molar ratio is 10.sup.2 or more and 1.0 or less; and an S/(Sb+M+V) molar ratio is 10.sup.2 or more and 1.0 or less, and the M is Co.

11. The catalyst for nitrogen oxide reduction of claim 1, wherein the catalytic site is a vanadate composed of La, V, and O; an M/V molar ratio is 0.3 or more and 1.0 or less; a P/(Sb+M+V) molar ratio is 10.sup.2 or more and 1.0 or less; and an S/(Sb+M+V) molar ratio is 10.sup.2 or more and 1.0 or less, and the M is La.

12. A synthesis method of a catalyst for nitrogen oxide reduction, the method comprising: preparing a mixed solution by mixing a vanadium precursor solution and a rare-earth metal or transition metal precursor solution; inputting a support to the mixed solution; obtaining a solid after the inputting, and performing calcination; and functionalizing a part of a rare-earth metal vanadate or a transition metal vanadate represented by at least one of Chemical Formulas 1 to 3 below with H.sub.3-APO.sub.4.sup.A (A=1, 2, or 3) and SO.sub.B.sup.2 (B=3 or 4): [Chemical Formula 1] (TM).sub.XV.sub.2O.sub.X+5 (X is 1, 2, or 3; TM is one or more selected from the group consisting of Mn, Co, Ni, and Cu) [Chemical Formula 2] (RM)VO.sub.4 (RM is one or more selected from the group consisting of La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, and Lu) ##STR00008##

13. The synthesis method of a catalyst for nitrogen oxide reduction of claim 12, wherein the functionalizing with H.sub.3-APO.sub.4.sup.A is performed by a reaction gas containing PH.sub.3 and O.sub.2.

14. The synthesis method of a catalyst for nitrogen oxide reduction of claim 13, wherein the concentrations of PH.sub.3 and O.sub.2 in the reaction gas have ranges of 10 ppm to 10.sup.5 ppm.

15. The synthesis method of a catalyst for nitrogen oxide reduction of claim 13, wherein the functionalizing with H.sub.3-APO.sub.4.sup.A is performed at a flow rate of 10.sup.5 mL.Math.min.sup.1 to 10.sup.5 mL.Math.min.sup.1 under pressure conditions of 10.sup.5 bar to 10.sup.5 bar at a temperature of 100 C. to 800 C. for 0.1 to 24 hours.

16. The synthesis method of a catalyst for nitrogen oxide reduction of claim 12, wherein the functionalizing with H.sub.3-APO.sub.4.sup.A consists of stirring and drying a synthetic solvent and the catalyst, wherein the synthetic solvent includes one or more of phosphoric acid (H.sub.3PO.sub.4), ammonium phosphate ((NH.sub.4).sub.3PO.sub.4), ammonium monohydrogen phosphate ((NH.sub.4).sub.2HPO.sub.4), ammonium dihydrogen phosphate (NH.sub.4H.sub.2PO.sub.4), dimethyl phosphite ((CH.sub.3O).sub.2HPO), diethyl phosphite ((C.sub.2H.sub.5O).sub.2HPO), trimethyl phosphite ((CH.sub.3O).sub.3P), triethyl phosphite ((C.sub.2H.sub.5O).sub.3P), triisopropyl phosphite ((C.sub.3H.sub.7).sub.3P), and triphenyl phosphite ((C.sub.6H.sub.5O).sub.3P).

17. The synthesis method of a catalyst for nitrogen oxide reduction of claim 16, wherein the concentration of a phosphoric acid precursor contained in the synthetic solvent has a range of 10.sup.5 mol.Math.L.sup.1 to 10.sup.5 mol.Math.L.sup.1.

18. The synthesis method of a catalyst for nitrogen oxide reduction of claim 16, wherein the stirring is performed for 0.1 to 24 hours.

19. The synthesis method of a catalyst for nitrogen oxide reduction of claim 12, wherein the functionalizing with SO.sub.B.sup.2 is performed by a reaction gas containing SO.sub.2 and O.sub.2.

20. The synthesis method of a catalyst for nitrogen oxide reduction of claim 19, wherein the concentrations of SO.sub.2 and O.sub.2 ppm in the reaction gas have ranges of 10 ppm to 10.sup.5.

21. The synthesis method of a catalyst for nitrogen oxide reduction of claim 19, wherein the functionalizing with SO.sub.B.sup.2 is performed at a flow rate of 10.sup.5 mL.Math.min.sup.1 to 10.sup.5 mL.Math.min.sup.1 under pressure conditions of 10.sup.5 bar to 10.sup.5 bar at a temperature of 100 C. to 800 C. for 0.1 to 24 hours.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0037] The above and other objects, features and advantages of the present invention will become more apparent to those of ordinary skill in the art by describing exemplary embodiments thereof in detail with reference to the accompanying drawings, in which:

[0038] FIG. 1 shows high-resolution transmission electron microscopy (HRTEM) photographs of Comparative Examples 1 to 3 and Examples 1 to 7 according to an embodiment of the present invention;

[0039] FIG. 2 shows selected area electron diffraction (SAED) pattern photographs of Comparative Examples 1 to 3 and Examples 1 to 7 according to an embodiment of the present invention;

[0040] FIG. 3 shows HRTEM photographs of Comparative Examples 4 to 6 and Examples 8 to 10 according to an embodiment of the present invention;

[0041] FIG. 4 shows SAED pattern photographs of Comparative Examples 4 to 6 and Examples 8 to 10 according to an embodiment of the present invention; and

[0042] FIGS. 5 to 14 show graphs illustrating NO.sub.X conversion under various selective catalytic nitrogen oxides (NO.sub.X) reduction (SCR) conditions of catalysts synthesized according to Comparative Examples and Examples according to an embodiment of the present invention.

DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS

[0043] Hereinafter, the present invention will be described in more detail. However, the present invention may be implemented in various different forms and the present invention is not limited to the embodiments described herein, and the present invention is only defined by the claims that will be described later.

[0044] In addition, the terms used herein are only used to describe specific embodiments and are not intended to limit the present invention. Unless the context clearly indicates otherwise, the singular expression includes the plural expression. Throughout the specification of the present invention, unless otherwise specified, the term comprising means that other components may be included rather than meaning that other components are excluded.

[0045] Throughout the specification, when a portion is described to be connected (linked, contacted, joined) to another portion, this includes not only cases where it is directly connected but also cases where it is indirectly connected with another member therebetween. Also, when a portion is described to comprise a certain component, unless otherwise specified, this means that other components may be included rather than meaning that other components are excluded.

[0046] The terms used herein are only used to describe specific embodiments and are not intended to limit the present invention. Unless the context clearly indicates otherwise, the singular expression includes the plural expression.

[0047] A first aspect of the present invention provides a catalyst for nitrogen oxide reduction, including: a catalyst site including one or more represented by Chemical Formulas 1 to 3 below; and a support on which the catalyst site is supported; wherein the catalyst site is functionalized with H.sub.3-APO.sub.4.sup.A (A=1, 2, or 3) and SO.sub.B.sup.2 (B=3 or 4):

[Chemical Formula 1]

[0048] (TM).sub.XV.sub.2O.sub.X+5 (X is 1, 2, or 3; TM is one or more selected from the group consisting of Mn, Co, Ni, and Cu)

[Chemical Formula 2]

[0049] (RM)VO.sub.4 (RM is one or more selected from the group consisting of La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, and Lu)

##STR00005##

[0050] Hereinafter, the catalyst for nitrogen oxide reduction according to the first aspect of the present invention will be described in detail.

[0051] In one embodiment of the present invention, the catalyst may further include a promoter site, which is an oxide of a Group 15 or 16 element, on the support.

[0052] In one embodiment of the present invention, the promotor site may be included in an amount of 10.sup.5% by weight to 50% by weight based on the support.

[0053] In one embodiment of the present invention, the Group 15 or 16 element may be included in a combination of one or more of nitrogen (N), phosphorus (P), sulfur (S), arsenic (As), selenium (Se), antimony (Sb), tellurium (Te), bismuth (Bi), polonium (Po), moscovium (Mc), and livermorium (Lv).

[0054] In one embodiment of the present invention, the support may include one of carbon (C), Al.sub.2O.sub.3, MgO, ZrO.sub.2, CeO.sub.2, TiO.sub.2, and SiO.sub.2.

[0055] In one embodiment of the present invention, the transition metal vanadate or rare-earth metal vanadate represented by one or more of the Chemical Formulas 1 to 3 may include a transition metal (TM) or a rare-earth metal (RM), each of which may be included in an amount of 10.sup.5% by weight to 50% by weight based on 100% by weight of the support.

[0056] In one embodiment of the present invention, the support may have a porous structure.

[0057] In one specific embodiment of the present invention, the catalytic site may be a vanadate composed of Ni, V, and O; wherein a Brunauer-Emmett-Teller (BET) surface area may be 65 m.sup.2/g or more and 71 or less m.sup.2/g; an M/V molar ratio may be 0.5 or more and 1.5 or less; a P/(Sb+M+V) molar ratio may be 10.sup.2 or more and 1.0 or less; and an S/(Sb+M+V) molar ratio may be 10.sup.2 or more and 1.0 or less, and preferably, the catalytic site may be one of NiV.sub.2O.sub.6, Ni.sub.2V.sub.2O.sub.7, and Ni.sub.3V.sub.2O.sub.8. The M may preferably be a TM or an RM, more preferably a TM, and most preferably Ni.

[0058] In one specific embodiment of the present invention, the catalytic site may be a vanadate composed of Mn, V, and O; wherein an M/V molar ratio may be 0.5 or more and 1.5 or less; a P/(Sb+M+V) molar ratio may be 10.sup.2 or more and 1.0 or less; and an S/(Sb+M+V) molar ratio may be 10.sup.2 or more and 1.0 or less, and preferably, the catalytic site may be one of MnV.sub.2O.sub.6, Mn.sub.2V.sub.2O.sub.7, and Mn.sub.3V.sub.2O.sub.8. The M may preferably be a TM or an RM, more preferably a TM, and most preferably Mn.

[0059] In one specific embodiment of the present invention, the catalytic site may be a vanadate composed of Co, V, and O; wherein a BET surface area may be 62 m.sup.2/g or more and 66.5 or less m.sup.2/g; an M/V molar ratio may be 0.5 or more and 1.5 or less; a P/(Sb+M+V) molar ratio may be 10.sup.2 or more and 1.0 or less; and an S/(Sb+M+V) molar ratio may be 10.sup.2 or more and 1.0 or less, and preferably, the catalytic site may be one of CoV.sub.2O.sub.6, Co.sub.2V.sub.2O.sub.7, and Co.sub.3V.sub.2O.sub.8. The M may preferably be a TM or an RM, more preferably a TM, and most preferably Co.

[0060] In one specific embodiment of the present invention, the catalytic site may be a vanadate composed of La, V, and O; wherein a BET surface area may be 71 or less m.sup.2/g; an M/V molar ratio may be 0.3 or more and 1.0 or less; a P/(Sb+M+V) molar ratio may be 10.sup.2 or more and 1.0 or less; and an S/(Sb+M+V) molar ratio may be 10.sup.2 or more and 1.0 or less, and preferably, the catalytic site may be one of LaVO.sub.4 and LaV.sub.3O.sub.9. The M may preferably be a TM or an RM, more preferably a TM, and most preferably La.

[0061] A second aspect of the present invention provides a synthesis method of a catalyst for nitrogen oxide reduction, the method including: preparing a mixed solution by mixing a vanadium precursor solution and a rare-earth metal or transition metal precursor solution; inputting a support to the mixed solution; obtaining a solid after the inputting, and performing calcination; and functionalizing a part of a rare-earth metal vanadate or a transition metal vanadate represented by at least one of Chemical Formulas 1 to 3 below with H.sub.3-APO.sub.4.sup.A (A=1, 2, or 3) and SO.sub.B.sup.2 (B=3 or 4):

[Chemical Formula 1]

[0062] (TM).sub.XV.sub.2O.sub.X+5 (X is 1, 2, or 3; TM is one or more selected from the group consisting of Mn, Co, Ni, and Cu)

[Chemical Formula 2]

[0063] (RM)VO.sub.4 (RM is one or more selected from the group consisting of La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, and Lu)

##STR00006##

[0064] For parts that overlap with the first aspect of the present invention, a detailed description has been omitted, but the contents described for the first aspect of the present invention may be equally applied even when the description has been omitted for the second aspect.

[0065] Hereinafter, the synthesis method of a catalyst for nitrogen oxide reduction according to the second aspect of the present invention will be described in detail.

[0066] In one embodiment of the present invention, the functionalizing with H.sub.3-APO.sub.4.sup.A may be performed by a reaction gas containing PH.sub.3 and O.sub.2.

[0067] In one embodiment of the present invention, the concentrations of PH.sub.3 and O.sub.2 in the reaction gas may have ranges of 10 ppm to 10 ppm.

[0068] In one embodiment of the present invention, the functionalizing with H.sub.3-APO.sub.4.sup.A may be performed at a flow rate of 10.sup.5 mL.Math.min.sup.1 to 10.sup.5 mL.Math.min.sup.1 under pressure conditions of 10.sup.5 bar to 10.sup.5 bar at a temperature of 100 C. to 800 C. for 0.1 to 24 hours.

[0069] In one embodiment of the present invention, the functionalizing with H.sub.3-APO.sub.4.sup.A may consist of stirring and drying a synthetic solvent and the catalyst, wherein the synthetic solvent may include one or more of phosphoric acid (H.sub.3PO.sub.4), ammonium phosphate ((NH.sub.4).sub.3PO.sub.4), ammonium monohydrogen phosphate ((NH.sub.4).sub.2HPO.sub.4), ammonium dihydrogen phosphate (NH.sub.4H.sub.2PO.sub.4), dimethyl phosphite ((CH.sub.3O).sub.2HPO), diethyl phosphite ((C.sub.2H.sub.5O).sub.2HPO), trimethyl phosphite ((CH.sub.3O).sub.3P), triethyl phosphite ((C.sub.2H.sub.5O).sub.3P), triisopropyl phosphite ((C.sub.3H.sub.7).sub.3P), and triphenyl phosphite ((C.sub.6H.sub.5O).sub.3P).

[0070] In one embodiment of the present invention, the stirring may be performed for 0.1 to 24 hours.

[0071] In one embodiment of the present invention, the functionalizing with SO.sub.B.sup.2 may be performed by a reaction gas containing SO.sub.2 and O.sub.2.

[0072] In one embodiment of the present invention, the concentrations of SO.sub.2 and O.sub.2 in the reaction gas may have ranges of 10 ppm to 10 ppm.

[0073] In one embodiment of the present invention, the functionalizing with SO.sub.B.sup.2 may be performed at a flow rate of 10.sup.5 mL.Math.min.sup.1 to 10.sup.5 mL.Math.min.sup.1 under pressure conditions of 10-5 bar to 10.sup.5 bar at a temperature of 100 C. to 800 C. for 0.1 to 24 hours.

[0074] Hereinafter, examples of the present invention will be described in detail so that those skilled in the art can easily implement the present invention. However, the present invention may be implemented in various different forms and is not limited to the examples described herein.

Examples 1 to 5: Synthesis of Ni.SUB.1.Sb-0.5PS300, Ni.SUB.1.Sb-0.25PS300, Ni.SUB.1.Sb-1.0PS300, Ni.SUB.1.Sb-0.5PS400, and Ni.SUB.1.Sb-0.5PS500 Catalysts

[0075] Ni.sub.1Sb-0.5PS300, Ni.sub.1Sb-0.5PS400, and Ni.sub.1Sb-0.5PS500, which are Examples 1, 4, and 5, were synthesized by loading Ni.sub.1Sb-0.5P into a reactor, allowing 500 ppm SO.sub.2 and 3% by volume of O.sub.2 diluted with N.sub.2 to flow into the reactor for one hour under normal pressure at 500 mL.Math.min.sup.1 at 300 C., 400 C., 500 C., respectively, and cooling the resulting products to room temperature in N.sub.2 atmosphere.

[0076] Ni.sub.1Sb-0.25PS300 and Ni.sub.1Sb-1.0PS300, which are Examples 2 and 3, were synthesized by the same synthesis method as Ni.sub.1Sb-0.5PS300 of Example 1, except that 0.11 mmol of (NH.sub.4).sub.2HPO.sub.4 or 0.44 mmol of (NH.sub.4).sub.2HPO.sub.4 was used instead of 0.22 mmol of (NH.sub.4).sub.2HPO.sub.4.

Examples 6 and 7: Synthesis of Ni.SUB.2.Sb-0.5PS300 and Ni.SUB.3.Sb-0.5PS300 Catalysts

[0077] 2.36 mmol of NH.sub.4VO.sub.3 and 2.36 mmol of Ni(NO.sub.3).sub.2.Math.6H.sub.2O were dissolved in 200 mL of distilled water, and the resulting mixture was stirred for one hour, then 5.74 g of Sb.sub.2O.sub.5TiO.sub.2 was added, and the resulting mixture was stirred for 18 hours.

[0078] After stirring and dehydrating this, Ni.sub.2Sb was synthesized by calcination at 500 C. for five hours. In addition, 2.36 mmol of NH.sub.4VO.sub.3 and 3.54 mmol of Ni(NO.sub.3).sub.2.Math.6H.sub.2O were dissolved in 200 mL of distilled water, and the resulting mixture was stirred for one hour, and then 5.67 g of Sb.sub.2O.sub.5TiO.sub.2 was added, and the resulting mixture was stirred for 18 hours. After stirring and dehydrating this, Ni.sub.3Sb was synthesized by calcination at 500 C. for five hours. 3 g of Ni.sub.2Sb or Ni.sub.3Sb catalyst was added to 140 mL of distilled water in which 0.22 mmol of (NH.sub.4).sub.2HPO.sub.4 was dissolved, and the resulting mixture was stirred at room temperature for 18 hours. After stirring and dehydrating this, calcination was performed at 500 C. for one hour to synthesize Ni.sub.2Sb-0.5P or Ni.sub.3Sb-0.5P. Ni.sub.2Sb-0.5PS300 or Ni.sub.3Sb-0.5PS500, which are Examples 6 and 7, were synthesized by loading Ni.sub.2Sb-0.5P or Ni.sub.3Sb-0.5P into a reactor, allowing 500 ppm SO.sub.2 and 3% by volume of O.sub.2 diluted with N.sub.2 to flow into the reactor for one hour under normal pressure at 500 mL.Math.min.sup.1 at 300 C., and cooling the resulting product to room temperature in N.sub.2 atmosphere.

Examples 8 to 10: Synthesis of Mn.SUB.1.Sb-0.5PS300.Math.Mn.SUB.2.Sb-0.5PS300, and Mn.SUB.3.Sb-0.5PS300 catalysts

[0079] Mn.sub.1Sb-0.5PS300, which is Example 8, was synthesized by loading Mn.sub.1Sb-0.5P, which is Comparative Example 6, into a reactor, allowing 500 ppm SO.sub.2 and 3% by volume of O.sub.2 diluted with N.sub.2 to flow into the reactor for one hour under normal pressure at 500 mL.Math.min.sup.1 at 300 C., and cooling the resulting product to room temperature in N.sub.2 atmosphere. Mn.sub.2Sb-0.5PS300 and Mn.sub.3Sb-0.5PS300, which are Examples 9 and 10, were synthesized in the same manner as Ni.sub.2Sb-0.5PS300 and Ni.sub.3Sb-0.5PS300 of Examples 6 and 7, except that 2.36 mmol of Mn(NO.sub.3).sub.2.Math.XH.sub.2O was used instead of 2.36 mmol of Ni(NO.sub.3).sub.2.Math.6H.sub.2O or 3.54 mmol of Mn(NO.sub.3).sub.2.Math.XH.sub.2O was used instead of 3.54 mmol of Ni(NO.sub.3).sub.2.Math.6H.sub.2O.

Examples 11 to 13: Synthesis of Co.SUB.1.Sb-0.5PS300, Co.SUB.2.Sb-0.5PS300, and Co.SUB.3.Sb-0.5S300 Catalysts

[0080] Co.sub.1Sb-0.5PS300, which is Example 11, was synthesized by loading Co.sub.1Sb-0.5P, which is Comparative Example 9, into a reactor, allowing 500 ppm SO.sub.2 and 3% by volume of O.sub.2 diluted with N.sub.2 to flow into the reactor for one hour under normal pressure at 500 mL.Math.min.sup.1 at 300 C., and cooling the resulting product to room temperature in N.sub.2 atmosphere. Co.sub.2Sb-0.5PS300 and Co.sub.3Sb-0.5PS300, which are Examples 12 and 13, were synthesized in the same manner as Ni.sub.2Sb-0.5PS300 and Ni.sub.3Sb-0.5PS300 of Examples 6 and 7, except that 2.36 mmol of Co(NO.sub.3).sub.2.Math.6H.sub.2O was used instead of 2.36 mmol of Ni(NO.sub.3).sub.2.Math.6H.sub.2O or 3.54 mmol of Co(NO.sub.3).sub.2.Math.6H.sub.2O was used instead of 3.54 mmol of Ni(NO.sub.3).sub.2.Math.6H.sub.2O.

Examples 14 and 15: Synthesis of LaVSb-0.5PS300 and LaV.SUB.3.Sb-0.5PS300

[0081] LaVSb-0.5PS300, which is Example 14, and LaV.sub.3Sb-0.5PS300, which is Example 15, were synthesized by respectively loading LaVSb-0.5P, which is Comparative Example 12, and LaV.sub.3Sb-0.5P, which is Comparative Example 15, into a reactor, allowing 500 ppm SO.sub.2 and 3% by volume of O.sub.2 diluted with N.sub.2 to flow into the reactor for one hour under normal pressure at 500 mL.Math.min.sup.1 at 300 C., and cooling the resulting product to room temperature in N.sub.2 atmosphere.

Comparative Examples 1, 4, 7, 10, and 13: Synthesis of: Ni.SUB.1.Sb, Mn.SUB.1.Sb, Co.SUB.1.Sb, LaVSb, and LaV.SUB.3.Sb Catalysts

[0082] 48.5 g of TiO.sub.2 was added to 350 mL of an acetic acid solution containing 12.32 mmol of Sb(CH.sub.3COO).sub.3, and the resulting mixture was stirred and dehydrated, and then calcined at 500 C. for five hours to prepare a TiO.sub.2 support (Sb.sub.2O/TiO.sub.2) on which Sb.sub.2O.sub.5, a promoter site, was dispersed. 2.36 mmol of NH.sub.4VO.sub.3 and 1.18 mmol of Ni(NO.sub.3).sub.2.Math.6H.sub.2O were dissolved in 200 mL of distilled water, and the resulting mixture was stirred for one hour, and then 5.81 g of Sb.sub.2O.sub.5/TiO.sub.2 was added, and the resulting mixture was stirred for 18 hours. After dehydrating this, the product was calcined at 500 C. for five hours to synthesize Ni.sub.1Sb, which was named as Comparative Example 1. Mn.sub.1Sb, which is Comparative Example 4, was synthesized in the same manner as Comparative Example 1, except that 1.18 mmol of Mn(NO.sub.3).sub.2.Math.XH.sub.2O was used instead of 1.18 mmol of Ni(NO.sub.3).sub.2.Math.6H.sub.2O. Co.sub.1Sb, which is Comparative Example 7, was synthesized in the same manner as Comparative Example 1, except that 1.18 mmol of Co(NO.sub.3).sub.2.Math.6H.sub.2O was used instead of 1.18 mmol of Ni(NO.sub.3).sub.2.Math.6H.sub.2O. LaVSb, which is Comparative Example 10, was synthesized in the same manner as Comparative Example 1, except that 2.36 mmol of La(NO.sub.3).sub.2.Math.6H.sub.2O was used instead of 1.18 mmol of Ni(NO.sub.3).sub.2.Math.6H.sub.2O, and 5.55 g of Sb.sub.2O.sub.5/SiO.sub.2 was used instead of 5.81 g of Sb.sub.2O.sub.5/SiO.sub.2. LaV.sub.3Sb, which is Comparative Example 13, was synthesized in the same manner as Comparative Example 1, except that 0.79 mmol of La(NO.sub.3).sub.2.Math.6H.sub.2O was used instead of 1.18 mmol of Ni(NO.sub.3).sub.2.Math.6H.sub.2O, and 5.77 g of Sb.sub.2O.sub.5/TiO.sub.2 was used instead of 5.81 g of Sb.sub.2O.sub.5/TiO.sub.2.

Comparative Examples 2, 5, 8, 11, and 14: Synthesis of Ni.SUB.1.Sb-300S, Mn.SUB.1.Sb-300S, Co.SUB.1.Sb-300S, LaVSb-300S, and LaV.SUB.3.Sb-300S Catalysts

[0083] Ni.sub.1Sb-300S, which is Comparative Example 2, Mn.sub.1Sb-300S, which is Comparative Example 5, Co.sub.1Sb-300S, which is Comparative Example 8, LaVSb-300S, which is Comparative Example 11, and LaV.sub.3Sb-300S, which is Comparative Example 14, were synthesized by respectively loading the catalysts of Ni.sub.1Sb, which is Comparative Example 1, Mn.sub.1Sb, which is Comparative Example 4, Co.sub.1Sb, which is Comparative Example 7, LaVSb, which is Comparative Example 10, and LaV.sub.3Sb, which is Comparative Example 13, into a reactor, allowing 500 ppm SO.sub.2 and 3% by volume of O.sub.2 diluted with N.sub.2 to flow into the reactor for one hour under normal pressure at 500 mL.Math.min.sup.1 at 300 C., and cooling the resulting product to room temperature in N.sub.2 atmosphere.

Comparative Examples 3, 6, 9, 12, and 15: Synthesis of Ni.SUB.1.Sb-0.5P, Mn.SUB.1.Sb-0.5P, Co.SUB.1.Sb-0.5P, LaVSb-0.5P, and LaV.SUB.3.Sb-0.5P Catalysts

[0084] 3 g of the catalysts of Ni.sub.1Sb, which is Comparative Example 1, Mn.sub.1Sb, which is Comparative Example 4, Co.sub.1Sb, which is Comparative Example 7, LaVSb, which is Comparative Example 10, and LaV.sub.3Sb, which is Comparative Example 13 were added to 140 mL of distilled water in which 0.22 mmol of (NH.sub.4).sub.2HPO.sub.4 was dissolved, and the resulting mixture was stirred at room temperature for 18 hours. After dehydrating this, the product was calcined at 500 C. for one hour to synthesize Ni.sub.1Sb-0.5P, which is Comparative Example 3, Mn.sub.1Sb-0.5P, which is Comparative Example 6, Co.sub.1Sb-0.5P, which is Comparative Example 9, LaVSb-0.5P, which is Comparative Example 12, or LaV.sub.3Sb-0.5P, which is Comparative Example 15.

[0085] The morphology of the catalysts synthesized in Comparative Examples 1 to 6 and Examples 1 to 10 was analyzed using high-resolution transmission electron microscopy (HRTEM), and the results are shown in FIGS. 1 and 3. Referring to these drawings, it can be seen that the synthesized catalysts exhibit porous characteristics due to TiO.sub.2 agglomerates having a size of several tens to several hundreds of nanometers. To quantify the porosity of the catalysts synthesized in Comparative Examples to 15 and Examples to 15, N.sub.2 physisorption experiments were performed to analyze and present the BET surface area and the Barrett-Joyner-Halenda (BJH) pore volume (Table 1). In addition, the components of the catalysts were analyzed using inductively coupled plasma spectroscopy, and the results are presented in Table 1 below.

TABLE-US-00001 TABLE 1 BET BJH P/ S/ Vanadate surface pore (Sb + (Sb + catalytic area volume M + M + Catalyst site (m.sup.2 g.sup.1) (cm.sup.3 g.sup.1) M/V.sup.1 V).sup.1 V).sup.1 Comparative NiV.sub.2O.sub.6 75.2 0.3 0.5 Example 1 Comparative NiV.sub.2O.sub.6 67.6 0.3 0.5 0.2 Example 2 Comparative NiV.sub.2O.sub.6 70.1 0.3 0.5 0.1 Example 3 Example 1 NiV.sub.2O.sub.6 68.7 0.3 0.5 0.1 0.1 Example 2 NiV.sub.2O.sub.6 66.1 0.3 0.5 0.1 0.1 Example 3 NiV.sub.2O.sub.6 69.2 0.3 0.5 0.2 0.1 Example 4 NiV.sub.2O.sub.6 70.1 0.3 0.5 0.1 0.1 Example 5 NiV.sub.2O.sub.6 66.0 0.3 0.5 0.1 0.1 Example 6 Ni.sub.2V.sub.2O.sub.7 68.7 0.3 1.0 0.1 0.2 Example 7 Ni.sub.3V.sub.2O.sub.8 65.4 0.3 1.5 0.1 0.2 Comparative MnV.sub.2O.sub.6 87.8 0.3 0.5 Example 4 Comparative MnV.sub.2O.sub.6 63.5 0.3 0.5 0.2 Example 5 Comparative MnV.sub.2O.sub.6 69.0 0.3 0.5 0.1 Example 6 Example 8 MnV.sub.2O.sub.6 68.9 0.3 0.5 0.1 0.1 Example 9 Mn.sub.2V.sub.2O.sub.7 69.0 0.3 1.0 0.1 0.2 Example 10 Mn.sub.3V.sub.2O.sub.8 67.3 0.3 1.5 0.1 0.2 Comparative CoV.sub.2O.sub.6 67.8 0.3 0.5 Example 7 Comparative CoV.sub.2O.sub.6 68.8 0.3 0.5 0.2 Example 8 Comparative CoV.sub.2O.sub.6 66.8 0.3 0.5 0.1 Example 9 Example 11 CoV.sub.2O.sub.6 68.3 0.3 0.5 0.1 0.1 Example 12 Co.sub.2V.sub.2O.sub.7 63.4 0.3 1.0 0.1 0.2 Example 13 Co.sub.3V.sub.2O.sub.8 62.4 0.3 1.5 0.1 0.2 Comparative LaVO.sub.4 73.7 0.3 1.0 Example 10 Comparative LaVO.sub.4 77.3 0.3 1.0 0.2 Example 11 Comparative LaVO.sub.4 72.5 0.3 1.0 0.1 Example 12 Example 14 LaVO.sub.4 70.6 0.3 1.0 0.1 0.2 Comparative LaV.sub.3O.sub.9 75.0 0.3 0.3 Example 13 Comparative LaV.sub.3O.sub.9 72.7 0.3 0.3 0.2 Example 14 Comparative LaV.sub.3O.sub.9 74.8 0.3 0.3 0.1 Example 15 Example 15 LaV.sub.3O.sub.9 69.5 0.3 0.3 0.1 0.1 .sup.1M is a TM or an RM.

[0086] From the BET surface area and BJH pore volume results, it was confirmed that the catalysts synthesized in Comparative Examples 1 to 15 and Examples 1 to 15 had a porous structure. In addition, the V contents of the catalysts were almost the same as 2% by weight based on the total weight of the catalysts. In addition, it was found that the M/V molar ratios of the catalysts of the comparative examples and the examples had values close to the M/V molar ratio of the vanadate inherent in the catalysts. For example, the MN values of the catalysts of Comparative Examples 1 to 3 and Examples 1 to 5 were close to the theoretical Ni/V value of 0.5 for NiV.sub.2O.sub.6, and the MN values of the catalysts of Examples 2 and 3 were close to the theoretical Ni/V values of 1.0 and 1.5 for Ni.sub.2V.sub.2O.sub.7 and Ni.sub.3V.sub.2O.sub.8, respectively. Based on this, it was found that the catalysts of Comparative Examples 1 to 3 and Examples 1 to 5 successfully dispersed NiV.sub.2O.sub.6 on the porous TiO.sub.2 surface, the catalyst of Example 6 successfully dispersed Ni.sub.2V.sub.2O.sub.7 on the porous TiO.sub.2 surface, and the catalyst of Example 7 successfully dispersed Ni.sub.3V.sub.2O.sub.8 on the porous TiO.sub.2 surface.

[0087] In addition, it was found that the S/(Sb+M+V) molar ratio of the catalysts synthesized in Comparative Examples 1 to 15 and Examples 1 to 15 (except Comparative Examples 1, 4, 7, 10, and 13) functionalized with H.sub.3-APO.sub.4.sup.A or SO.sub.B.sup.2 was 0.1 to 0.2, and the P/(Sb+M+V) molar ratio was 0.1 to 0.2, indicating that their values were almost the same. This means that the functionalization of the catalysts synthesized in Comparative Examples 1 to 15 and Examples 1 to 15 (except Comparative Examples 1, 4, 7, 10, and 13) with H.sub.3-APO.sub.4.sup.A or SO.sub.B.sup.2 was performed to a similar degree.

[0088] The crystal structures of the catalysts synthesized in Comparative Examples 1 to 6 and Examples 1 to 10 were analyzed using selected area electron diffraction (SAED) patterns, and the results are shown in FIGS. 2 and 4. The SAED patterns of all the synthesized catalysts include crystal planes of cubic Sb.sub.2O.sub.5 and tetragonal TiO.sub.2, which is due to the Sb.sub.2O.sub.5 promoter sites and TiO.sub.2 support inherent in the catalysts.

[0089] Referring to the SAED patterns of FIG. 2, the catalysts of Comparative Examples 1 to 3 and Examples 1 to 5 include a crystal plane of triclinic NiV.sub.2O.sub.6, the catalyst of Example 6 includes a crystal plane of monoclinic Ni.sub.2V.sub.2O.sub.7, and the catalyst of Example 7 includes a crystal plane of orthorhombic Ni.sub.3V.sub.2O.sub.8.

[0090] Referring to the SAED patterns of FIG. 4, the catalysts of Comparative Examples 4 to 6 and Example 8 include a crystal plane of monoclinic MnV.sub.2O.sub.6, the catalyst of Example 9 includes a crystal plane of monoclinic Mn.sub.2V.sub.2O.sub.7, and the catalyst of Example 10 includes a crystal plane of orthorhombic Mn.sub.3V.sub.2O.sub.8.

[0091] As shown in FIGS. 2 and 4, in the SAED of the catalysts synthesized in Comparative Examples 1 to 6 and Examples 1 to 10, no SAED patterns of substances other than the TM vanadates, for example, vanadium oxide or TM oxides, were observed. In other words, it was found that the catalysts synthesized in Comparative Examples 1 to 6 and Examples 1 to 10 of the present invention only contain vanadates, which are oxides in which vanadium oxide and transition metal oxide are fused into one, and do not contain vanadium oxide and transition metal oxide separately.

[0092] Hereinafter, referring to FIGS. 5 to 14, the SCR reaction performance using the catalysts synthesized in Comparative Examples 1 to 15 and Examples 1 to 15 will be described.

Experimental Example 1: Performance Analysis of SCR Reaction I

[0093] The performance of the SCR reaction in the absence of SO.sub.2 was measured using the catalysts of Comparative Examples 1 to 3 and Example 1. Specifically, the performance of the above-described catalysts was measured in a reaction fluid containing 800 ppm of NO.sub.X, 800 ppm of NH.sub.3, 3% by volume of 02, 6% by volume of H.sub.2O, and N.sub.2, which is an inert gas, at a spatial velocity of 60,000 hr.sup.1, and the NO.sub.X conversion (X.sub.NOX) results are shown in FIG. 5A. All the catalysts exhibited 100% N.sub.2 selectivity in the temperature range of 150 C. to 300 C. Referring to FIG. 5A, it can be seen that the catalysts of Comparative Example 2 or 3, whose catalyst surfaces were functionalized with SO.sub.B.sup.2 or H.sub.3-APO.sub.4.sup.A, exhibited larger X.sub.NOX values at 150 C. to 300 C. than those of the catalyst of Comparative Examples 1, whose catalyst surfaces were not functionalized. This means that the functionalization of the TM (nickel) vanadate with SO.sub.B.sup.2 or H.sub.3-APO.sub.4.sup.A is effective in increasing the number of Brnsted acids for NH.sub.3 adsorption, and that the SO.sub.B.sup.2 or H.sub.3-APO.sub.4.sup.A functional groups are effective in increasing the redox cycling characteristics of the catalyst surface. In addition, it can be seen that the catalyst of Example 1 functionalized with SO.sub.B.sup.2 and H.sub.3-APO.sub.4.sup.A exhibited larger X.sub.NOX values at 150 C. to 300 C. than those of the catalysts of Comparative Example 1, 2, or 3, which were unfunctionalized, functionalized with SO.sub.B.sup.2 or functionalized with H.sub.3-APO.sub.4.sup.A This means that the SO.sub.B.sup.2 and H.sub.3-APO.sub.4.sup.A functional groups inherent on the surface of the TM (nickel) vanadate have a synergistic effect in increasing the number of Brnsted acids for NH.sub.3 adsorption and increasing the redox cycling characteristics of the catalyst surface. In addition, the performance of the SCR reaction in the presence of SO.sub.2 was measured using the catalysts of Comparative Examples 2 and 3 and Example 1. Specifically, the performance of the above-described catalysts was measured in a reaction fluid containing 800 ppm of NO.sub.X, 800 ppm of NH.sub.3, 500 ppm of SO.sub.2, 3% by volume of 02, 6% by volume of H.sub.2O, and N.sub.2, which is an inert gas, at a spatial velocity of 60,000 hr.sup.1, and the NO.sub.X conversion (X.sub.NOX) results are shown in FIG. 5B. All the catalysts exhibited 100% N.sub.2 selectivity in the temperature range of 150 C. to 300 C. Referring to FIG. 5B, it can be seen that the catalyst of Comparative Example 3 functionalized with H.sub.3-APO.sub.4.sup.A and the catalyst of Example 1 functionalized with SO.sub.B.sup.2 and H.sub.3-APO.sub.4.sup.A exhibited larger X.sub.NOX values at 150 C. to 300 C. than those of the catalyst of Comparative Example 2 functionalized with SO.sub.B.sup.2. This means that the catalyst surface including the H.sub.3-APO.sub.4.sup.A functional group may be preferable for increasing the resistance to SO.sub.2. On the other hand, although the catalyst of Example 1 functionalized with SO.sub.B.sup.2 and H.sub.3-APO.sub.4.sup.A exhibited increased X.sub.NOX values compared to the catalyst of Comparative Example 3 functionalized with H.sub.3-APO.sub.4.sup.A at 180 C. to 200 C., the X.sub.NOX values of the two catalysts were similar in the temperature range of 150 C. to 300 C. This means that in order to maximize the synergistic effect of SO.sub.B.sup.2 and H.sub.3-APO.sub.4.sup.A inherent in the catalyst surfaces, it is important to preferably control and select the functionalization conditions of SO.sub.B.sup.2 and H.sub.3-APO.sub.4.sup.A, such as the type of TM vanadate, the concentrations of SO.sub.B.sup.2 and H.sub.3-APO.sub.4.sup.A precursors (SO.sub.2/O.sub.2 and (NH.sub.4).sub.2HPO.sub.4), and the exposure time/exposure temperature to the catalyst surfaces.

Experimental Example 2: Performance Analysis of SCR Reaction II

[0094] The performance of the SCR reaction in the absence of SO.sub.2 was measured using the catalysts of Comparative Example 1 and Examples 1 to 3. Specifically, the performance of the above-described catalysts was measured under the same conditions as in FIG. 5A of Experimental Example 1, and the nitrogen oxide conversion (NO.sub.X conversion, X.sub.NOX) results are shown in FIG. 6. All the catalysts exhibited 100% N.sub.2 selectivity in the temperature range of 150 C. to 300 C. Referring to FIG. 6, it can be seen that the catalysts of Examples 1 to 3, whose catalyst surfaces were functionalized with SO.sub.B.sup.2 and H.sub.3-APO.sub.4.sup.A exhibited larger X.sub.NOX values at 150 C. to 300 C. than those of the catalyst of Comparative Example 1, whose catalyst surface was not functionalized. This means that the functionalization of the TM (nickel) vanadate with SO.sub.B.sup.2 and H.sub.3-APO.sub.4.sup.A is effective in increasing the number of Brnsted acids for the adsorption of NH.sub.3, and that the SO.sub.B.sup.2 and H.sub.3-APO.sub.4.sup.A functional groups are effective in increasing the redox cycling characteristics of the catalyst surface. In addition, in the cases of Example 1 (Ni.sub.1Sb-0.5PS300), Example 2 (Ni.sub.1Sb-0.25PS300), and Example 3 (Ni.sub.1Sb-1.0PS300), which were functionalized with SO.sub.B.sup.2 and H.sub.3-APO.sub.4.sup.A but with different amounts of H.sub.3-APO.sub.4.sup.A, it was found that the X.sub.NOX values increased in the order of Example 3<Example 1<Example 2 at 250 C. This means that the synergistic effect of the SO.sub.B.sup.2 and H.sub.3-APO.sub.4.sup.A functional groups inherent on the surface of TM (nickel) vanadate on increasing the number of Brnsted acids for NH.sub.3 adsorption and increasing the redox cycling characteristics of the catalyst surface depends on the number of H.sub.3-APO.sub.4.sup.A functional groups and is maximized in Example 2 (Ni.sub.1Sb-0.25PS300).

Experimental Example 3: Performance Analysis of SCR Reaction III

[0095] The performance of the SCR reaction in the absence of SO.sub.2 was measured using the catalysts of Examples 1, 4, and 5. Specifically, the performance of the above-described catalysts was measured under the same conditions as in FIG. 5A of Experimental Example 1, and the nitrogen oxide conversion (NO.sub.X conversion, X.sub.NOX) results are shown in FIG. 7. All the catalysts exhibited 100% N.sub.2 selectivity in the temperature range of 150 C. to 300 C. Referring to FIG. 7, it can be seen that the catalysts of Examples 1 and 4 functionalized with SO.sub.B.sup.2 at 300 C. and 400 C. exhibited larger X.sub.NOX values at 150 C. to 300 C. than those of the catalyst of Example 5 functionalized with SO.sub.B.sup.2 at 500 C. This means that in order to maximize the synergistic effect of SO.sub.B.sup.2 and H.sub.3-APO.sub.4.sup.A inherent in the catalyst surface, it is important to select a preferable exposure temperature of SO.sub.B.sup.2 precursors (SO.sub.2/O.sub.2) to the catalyst surfaces, as a SO.sub.B.sup.2 functionalization condition.

Experimental Example 4: Performance Analysis of SCR Reaction VI

[0096] The performance of the SCR reaction in the absence of SO.sub.2 was measured using the catalysts of Examples 1, 6, and 7. Specifically, the performance of the above-described catalysts was measured under the same conditions as in FIG. 5A of Experimental Example 1, and the results of the nitrogen oxide conversion (NO.sub.X conversion, X.sub.NOX) are shown in FIG. 8A. In addition, the performance of the SCR reaction in the presence of SO.sub.2 was measured using the catalysts of Examples 1, 6, and 7. Specifically, the performance of the above-described catalysts was measured under the same conditions as in FIG. 5B of Experimental Example 1, and the results of the nitrogen oxide conversion (NO.sub.X conversion, X.sub.NOX) are shown in FIG. 8B. All catalysts exhibited 100% N.sub.2 selectivity in the temperature range of 150 C. to 300 C. Referring to FIGS. 8A and 8B, it can be seen that when the crystal phase of the TM (nickel) vanadate on which the SO.sub.B.sup.2 and H.sub.3-APO.sub.4.sup.A functional groups are immobilized was NiV.sub.2O.sub.6, the value of X.sub.NOX was larger than that of Ni.sub.2V.sub.2O.sub.7, and when the crystal phase was Ni.sub.2V.sub.2O.sub.7, the value of X.sub.NOX was larger than that of Ni.sub.3V.sub.2O.sub.8. This means that in order to maximize the synergistic effect of SO.sub.B.sup.2 and H.sub.3-APO.sub.4.sup.A inherent in the catalyst surfaces, it is important to preferably control and select the crystal phase of the TM (nickel) vanadate on which the functional groups are immobilized.

Experimental Example 5: Performance Analysis of SCR Reaction V

[0097] The performance of the SCR reaction in the absence of SO.sub.2 was measured using the catalysts of Comparative Examples 4 to 6 and Example 8. Specifically, the performance of the above-described catalysts was measured under the same conditions as in FIG. 5A of Experimental Example 1, and the nitrogen oxide conversion (NO.sub.X conversion, X.sub.NOX) results are shown in FIG. 9A. In addition, the performance of the SCR reaction in the presence of SO.sub.2 was measured using the catalysts of Comparative Examples 5 and 6 and Example 8. Specifically, the performance of the above-described catalysts was measured under the same conditions as in FIG. 5B of Experimental Example 1, and the nitrogen oxide conversion (NO.sub.X conversion, X.sub.NOX) results are shown in FIG. 9B. All catalysts exhibited 100% N.sub.2 selectivity in the temperature range of 150 C. to 300 C. Referring to FIG. 9A, it can be seen that the catalyst of Comparative Example 5 or Comparative Example 6, whose catalyst surface was functionalized with SO.sub.B.sup.2 or H.sub.3-APO.sub.4.sup.A exhibited larger X.sub.NOX values at 150 C. to 300 C. than those of the catalyst of Comparative Example 4, whose catalyst surface was not functionalized. This means that the functionalization of the TM (manganese) vanadate with SO.sub.B.sup.2 or H.sub.3-APO.sub.4.sup.A is effective in increasing the number of Brnsted acids for NH.sub.3 adsorption, and that the SO.sub.B.sup.2 or H.sub.3-APO.sub.4.sup.A functional groups are effective in increasing the redox cycling characteristics of the catalyst surface. In addition, it can be seen that the catalyst of Example 8 functionalized with SO.sub.B.sup.2 and H.sub.3-APO.sub.4.sup.A exhibited a larger X.sub.NOX value at 200 C. than that of the catalyst of Comparative Example 4, 5, or 6, which was unfunctionalized, functionalized with SO.sub.B.sup.2, or functionalized with H.sub.3-APO.sub.4.sup.A. This means that the SO.sub.B.sup.2 and H.sub.3-APO.sub.4.sup.A functional groups inherent on the surface of transition metal (manganese) vanadate have a synergistic effect in increasing the number of Brnsted acids for NH.sub.3 adsorption and increasing the redox cycling characteristics of the catalyst surface. Also, referring to FIG. 9B, it can be seen that the catalyst of Comparative Example 5 functionalized with SO.sub.B.sup.2, the catalyst of Comparative Example 6 functionalized with H.sub.3-APO.sub.4.sup.A, and the catalyst of Example 8 functionalized with SO.sub.B.sup.2 and H.sub.3-APO.sub.4.sup.A exhibited similar X.sub.NOX values at 150 C. to 300 C. This means that in order to maximize the synergistic effect of SO.sub.B.sup.2 and H.sub.3-APO.sub.4.sup.A inherent on the catalyst surface, it is important to preferably control and select the functionalization conditions of SO.sub.B.sup.2 and H.sub.3-APO.sub.4.sup.A, for example, the type of TM vanadate, the concentrations of SO.sub.B.sup.2 and H.sub.3-APO.sub.4.sup.A precursors (SO.sub.2/O.sub.2 and (NH.sub.4).sub.2HPO.sub.4), and the exposure time/exposure temperature to the catalyst surfaces.

Experimental Example 6: Performance Analysis of SCR Reaction VI

[0098] The performance of the SCR reaction in the absence of SO.sub.2 was measured using the catalysts of Examples 8, 9, and 10. Specifically, the performance of the above-described catalysts was measured under the same conditions as in FIG. 5A of Experimental Example 1, and the results of the nitrogen oxide conversion (NO.sub.X conversion, X.sub.NOX) are shown in FIG. 10A. In addition, the performance of the SCR reaction in the presence of SO.sub.2 was measured using the catalysts of Examples 8, 9, and 10. Specifically, the performance of the above-described catalysts was measured under the same conditions as in FIG. 5B of Experimental Example 1, and the results of the nitrogen oxide conversion (NO.sub.X conversion, X.sub.NOX) are shown in FIG. 10B. All catalysts exhibited of 100% N.sub.2 selectivity in the temperature range of 150 C. to 300 C. Referring to FIG. 10A, it can be seen that when the crystal phases of the TM (manganese) vanadate on which SO.sub.B.sup.2 and H.sub.3-APO.sub.4.sup.A functional groups were immobilized were MnV.sub.2O.sub.6 and Mn.sub.2V.sub.2O.sub.7, the values of X.sub.NOX in the absence of SO.sub.2 were similar, whereas, when the crystal phase was Mn.sub.3V.sub.2O.sub.8, the value of X.sub.NOX in the absence of SO.sub.2 was smaller than that of MnV.sub.2O.sub.6/Mn.sub.2V.sub.2O.sub.7. On the other hand, referring to FIG. 10B, it can be seen that when the crystal phase of the TM (manganese) vanadate on which the SO.sub.B.sup.2 and H.sub.3-APO.sub.4.sup.A functional groups were immobilized was Mn.sub.3V.sub.2O.sub.8, the value of X.sub.NOX in the presence of SO.sub.2 was larger than that of MnV.sub.2O.sub.6/Mn.sub.2V.sub.2O.sub.7. This means that in order to maximize the synergistic effect of SO.sub.B.sup.2 and H.sub.3-APO.sub.4.sup.A inherent on the catalyst surface under various SCR reaction conditions, it is important to preferably select the crystal phase of the TM (manganese) vanadate on which the functional groups are immobilized.

Experimental Example 7: Performance Analysis of SCR Reaction VII

[0099] The performance of the SCR reaction in the absence of SO.sub.2 was measured using the catalysts of Comparative Examples 7 to 9 and Example 11. Specifically, the performance of the above-described catalysts was measured under the same conditions as in FIG. 5A of Experimental Example 1, and the nitrogen oxide conversion (NO.sub.X conversion, X.sub.NOX) results are shown in FIG. 11A. In addition, the performance of the SCR reaction in the presence of SO.sub.2 was measured using the catalysts of Comparative Examples 8 and 9 and Example 11. Specifically, the performance of the above-described catalysts was measured under the same conditions as in FIG. 5B of Experimental Example 1, and the nitrogen oxide conversion (NO.sub.X conversion, X.sub.NOX) results are shown in FIG. 11B. All catalysts exhibited 100% N.sub.2 selectivity of in the temperature range of 150 C. to 300 C. Referring to FIG. 11A, it can be seen that the catalyst of Comparative Example 8 or Comparative Example 9, whose catalyst surface was functionalized with SO.sub.B.sup.2 or H.sub.3-APO.sub.4.sup.A exhibited larger X.sub.NOX values at 150 C. to 300 C. than those of the catalyst of Comparative Example 7, whose catalyst surface was not functionalized. This means that the functionalization of the TM (cobalt) vanadate with SO.sub.B.sup.2 or H.sub.3-APO.sub.4.sup.A is effective in increasing the number of Brnsted acids for NH.sub.3 adsorption, and that the SO.sub.B.sup.2 or H.sub.3-APO.sub.4.sup.A functional groups is effective in increasing the redox cycling characteristics of the catalyst surface. In addition, it can be seen that the catalyst of Example 11, which was functionalized with SO.sub.B.sup.2 and H.sub.3-APO.sub.4.sup.A, exhibited larger X.sub.NOX values at 150 C. to 300 C. than those of the catalysts of Comparative Example 7 or 10 Comparative Example 8, which were unfunctionalized or functionalized with SO.sub.B.sup.2. This means that the SO.sub.B.sup.2 and H.sub.3-APO.sub.4.sup.A functional groups inherent on the surface of the TM (cobalt) vanadate may exhibit a synergistic in increasing the number of Brnsted acids for NH.sub.3 adsorption and increasing the redox cycling characteristics of the catalyst surface. On the other hand, referring to FIG. 11A, it can be seen that the catalyst of Example 11 functionalized with SO.sub.B.sup.2 and H.sub.3-APO.sub.4.sup.A exhibited similar X.sub.NOX values at 150 C. to 300 C. to the catalyst of Comparative Example 9 functionalized with H.sub.3-APO.sub.4.sup.A. In addition, referring to FIG. 11B, it can be seen that the catalyst of Comparative Example 9 functionalized with H.sub.3-APO.sub.4.sup.A and the catalyst of Example 11 functionalized with SO.sub.B.sup.2 and H.sub.3-APO.sub.4.sup.A exhibited larger X.sub.NOX values at 150 C. to 300 C. than those of the catalyst of Comparative Example 8 functionalized with SO.sub.B.sup.2. Nevertheless, referring to FIG. 11B, it can be seen that the catalyst of Comparative Example 9 functionalized with H.sub.3-APO.sub.4.sup.A and the catalyst of Example 11 functionalized with SO.sub.B.sup.2 and H.sub.3-APO.sub.4.sup.A exhibited similar X.sub.NOX values at 150 C. to 300 C. This means that in order to maximize the synergistic effect of SO.sub.B.sup.2 and H.sub.3-APO.sub.4.sup.A inherent on the catalyst surface, it is important to preferably control and select the functionalization conditions of SO.sub.B.sup.2 and H.sub.3-APO.sub.4.sup.A such as the type of TM vanadate, the concentrations of SO.sub.B.sup.2 and H.sub.3-APO.sub.4.sup.A precursors (SO.sub.2/O.sub.2 and (NH.sub.4).sub.2HPO.sub.4), and the exposure time/exposure temperature to the catalyst surfaces.

Experimental Example 8: Performance Analysis of SCR Reaction VIII

[0100] The performance of the SCR reaction in the absence of SO.sub.2 was measured using the catalysts of Examples 11, 12, and 13. Specifically, the performance of the above-described catalysts was measured under the same conditions as in FIG. 5A of Experimental Example 1, and the results of the nitrogen oxide conversion (NO.sub.X conversion, X.sub.NOX) are shown in FIG. 12A. In addition, the performance of the SCR reaction in the presence of SO.sub.2 was measured using the catalysts of Examples 11, 12, and 13. Specifically, the performance of the above-described catalysts was measured under the same conditions as in FIG. 5B of Experimental Example 1, and the results of the nitrogen oxide conversion (NO.sub.X conversion, X.sub.NOX) are shown in FIG. 12B. All catalysts exhibited 100% N.sub.2 selectivity in the temperature range of 150 C. to 300 C. Referring to FIG. 12A, it can be seen that when the crystal phase of the TM (cobalt) vanadate on which SO.sub.B.sup.2 and H.sub.3-APO.sub.4.sup.A functional groups were immobilized was CoV.sub.2O.sub.6, the value of X.sub.NOX was larger than that of Co.sub.2V.sub.2O.sub.7, and when the crystal phase was Co.sub.2V.sub.2O.sub.7, the value of X.sub.NOX was larger than that of Co.sub.3V.sub.2O.sub.8, in the absence of SO.sub.2. In addition, referring to FIG. 12B, it can be seen that when the crystal phase of the TM (cobalt) vanadate on which SO.sub.B.sup.2 and H.sub.3-APO.sub.4.sup.A functional groups were immobilized was CoV.sub.2O.sub.6, the value of X.sub.NOX was larger than that of Co.sub.2V.sub.2O.sub.7, and when the crystal phase was Co.sub.2V.sub.2O.sub.7, the value of X.sub.NOX was larger than that of Co.sub.3V.sub.2O.sub.8, in the presence of SO.sub.2. This means that in order to maximize the synergistic effect of SO.sub.B.sup.2 and H.sub.3-APO.sub.4.sup.A inherent on the catalyst surface under various SCR reaction conditions, it is important to preferably select a TM (cobalt) vanadate crystal phase on which functional groups are immobilized.

Experimental Example 9: Performance Analysis of SCR Reaction IX

[0101] The performance of the SCR reaction in the absence of SO.sub.2 was measured using the catalysts of Comparative Examples 10 to 12 and Example 14. Specifically, the performance of the above-described catalysts was measured under the same conditions as in FIG. 5A of Experimental Example 1, and the nitrogen oxide conversion (NO.sub.X conversion, X.sub.NOX) results are shown in FIG. 13A. In addition, the performance of the SCR reaction in the presence of SO.sub.2 was measured using the catalysts of Comparative Examples 11 to 12 and Example 14. Specifically, the performance of the above-described catalysts was measured under the same conditions as in FIG. 5B of Experimental Example 1, and the nitrogen oxide conversion (NO.sub.X conversion, X.sub.NOX) results are shown in FIG. 13B. All catalysts exhibited 100% N.sub.2 selectivity of in the temperature range of 150 C. to 300 C. Referring to FIG. 13A, it can be seen that the catalyst of Comparative Example 11 or Comparative Example 12, whose catalyst surface was functionalized with SO.sub.B.sup.2 or H.sub.3-APO.sub.4.sup.A, exhibited larger X.sub.NOX values at 150 C. to 300 C. than those of the catalyst of Comparative Example 10, whose catalyst surface was not functionalized. This means that the functionalization of the RM (lanthanum) vanadate with SO.sub.B.sup.2 or H.sub.3-APO.sub.4.sup.A is effective in increasing the number of Brnsted acids for NH.sub.3 adsorption, and that the SO.sub.B.sup.2 or H.sub.3-APO.sub.4.sup.A functional groups are effective in increasing the redox cycling characteristics of the catalyst surface. In addition, it can be seen that the catalyst of Example 14, which was functionalized with SO.sub.B.sup.2 and H.sub.3-APO.sub.4.sup.A, exhibited larger X.sub.NOX values at 150 C. to 300 C. than those of the catalyst of Comparative Example 10 or Comparative Example 11, which were unfunctionalized or functionalized with SO.sub.B.sup.2. This means that the SO.sub.B.sup.2 and H.sub.3-APO.sub.4.sup.A functional groups inherent on the surface of the RM (lanthanum) vanadate may have a synergistic effect in increasing the number of Brnsted acids for NH.sub.3 adsorption and increasing the redox cycling characteristics of the catalyst surface. On the other hand, referring to FIG. 13A, it can be seen that the catalyst of Example 14 functionalized with SO.sub.B.sup.2 and H.sub.3-APO.sub.4.sup.A exhibited similar X.sub.NOX values at 150 C. to 300 C. to the catalyst of Comparative Example 12 functionalized with H.sub.3-APO.sub.4.sup.A. In addition, referring to FIG. 13B, it can be seen that the catalyst of Comparative Example 11 functionalized with SO.sub.B.sup.2 the catalyst of Comparative Example 12 functionalized with H.sub.3-APO.sub.4.sup.A, and the catalyst of Example 14 functionalized with SO.sub.B.sup.2 and H.sub.3-APO.sub.4.sup.A exhibited similar X.sub.NOX values at 150 C. to 300 C. This means that in order to maximize the synergistic effect of SO.sub.B.sup.2 and H.sub.3-APO.sub.4.sup.A inherent on the catalyst surface, it is important to preferably control and select the functionalization conditions of SO.sub.B.sup.2 and H.sub.3-APO.sub.4.sup.A, for example, the type of the TM vanadate, the concentrations of SO.sub.B.sup.2 and H.sub.3-APO.sub.4.sup.A precursors (SO.sub.2/O.sub.2 and (NH.sub.4).sub.2HPO.sub.4), and the exposure time/exposure temperature to the catalyst surface.

Experimental Example 10: Performance Analysis of SCR Reaction X

[0102] The performance of the SCR reaction in the absence of SO.sub.2 was measured using the catalysts of Comparative Examples 13 to 15 and Example 15. Specifically, the performance of the above-described catalysts was measured under the same conditions as in FIG. 5A of Experimental Example 1, and the nitrogen oxide conversion (NO.sub.X conversion, X.sub.NOX) results are shown in FIG. 14A. In addition, the performance of the SCR reaction in the presence of SO.sub.2 was measured using the catalysts of Comparative Examples 14 and 15 and Example 15. Specifically, the performance of the above-described catalysts was measured under the same conditions as in FIG. 5B of Experimental Example 1, and the nitrogen oxide conversion (NO.sub.X conversion, X.sub.NOX) results are shown in FIG. 14B. All catalysts exhibited 100% N.sub.2 selectivity in the temperature range of 150 C. to 300 C. Referring to FIG. 14A, it can be seen that the X.sub.NOX of the catalyst of Comparative Example 13, whose catalyst surface was not functionalized, at 150 C. 300 C., was similar to the X.sub.NOX value of the catalysts of Comparative Example 14 or 15, whose catalyst surfaces were functionalized with SO.sub.B.sup.2 and H.sub.3-APO.sub.4.sup.A. This means that the functionalization of the RM (lanthanum) vanadate by SO.sub.B.sup.2 and H.sub.3-APO.sub.4.sup.A has a minimal effect in increasing the number of Brnsted acids for NH.sub.3 adsorption, and that the SO.sub.B.sup.2 and H.sub.3-APO.sub.4.sup.A functional groups have a minimal effect in increasing the redox cycling characteristics of the catalyst surface. On the other hand, it can be seen that the catalyst of Example 15 functionalized with SO.sub.B.sup.2 and H.sub.3-APO.sub.4.sup.A exhibited larger X.sub.NOX values at 150 C. to 300 C. than those of the catalysts of Comparative Example 13, which was unfunctionalized, Comparative Example 14, which was functionalized with SO.sub.B.sup.2 and Comparative Example 15, which was functionalized with H.sub.3-APO.sub.4.sup.A. This means that the SO.sub.B.sup.2 and H.sub.3-APO.sub.4.sup.A functional groups inherent on the surface of the RM metal (lanthanum) vanadate may have a synergistic effect in increasing the number of Brnsted acids for NH.sub.3 adsorption and increasing the redox cycling characteristics of the catalyst surface. On the other hand, referring to FIG. 14B, it can be seen that the catalyst of Comparative Example 14 functionalized with SO.sub.B.sup.2 the catalyst of Comparative Example 15 functionalized with H.sub.3-APO.sub.4.sup.A, and the catalyst of Example 15 functionalized with SO.sub.B.sup.2 and H.sub.3-APO.sub.4.sup.A exhibited similar X.sub.NOX values at 150 C. to 300 C. This means that in order to maximize the synergistic effect of SO.sub.B.sup.2 and H.sub.3-APO.sub.4.sup.A inherent on the catalyst surface, it is important to preferably control and select the functionalization conditions of SO.sub.B.sup.2 and H.sub.3-APO.sub.4.sup.A, for example, the type of the RM vanadate, the concentrations of SO.sub.B.sup.2 and H.sub.3-APO.sub.4.sup.A precursors (SO.sub.2/O.sub.2 and (NH.sub.4).sub.2HPO.sub.4), and the exposure time/exposure temperature to the catalyst surface.

[0103] According to one embodiment of the present invention, a catalyst may be synthesized by dispersing one or more metal vanadates including a transition metal (Mn, Co, Ni, and Cu) or a rare-earth metal (La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, and Lu) as a catalytic site on the surface, and by applying an oxide of a Group 15 or 16 element as a promoter site or functionalizing some of the catalytic sites with H.sub.3-APO.sub.4.sup.A and SO.sub.B.sup.2, to implement a catalytic surface having a high NO.sub.X conversion rate and a high N.sub.2 selectivity during selective catalytic NO.sub.X reduction (SCR) operation.

[0104] In addition, based on the functionalization of the catalyst surface using H.sub.3-APO.sub.4.sup.A and SO.sub.B.sup.2, 1) preferable interactions between acid sites/redox sites inherent in the catalytic site and NO.sub.X, NH.sub.3, and H.sub.2O can be induced, 2) redox cycling characteristics can be improved, or 3) resistance to poisoning (H.sub.2O, SO.sub.2, ABS, and alkali-metal) or hydro-thermal aging that may occur during the SCR reaction can be enhanced. Based on these advantages, there is an effect of dramatically improve the performance and lifespan of the SCR catalyst.

[0105] It should be understood that the effects of the present invention are not limited to the above-described effects, but include all effects that may be inferred from the features of the invention described in the detailed description or claims of the present invention.

[0106] The above description of the present invention is for illustrative purposes, and those skilled in the art will understand that the present invention may be easily modified into other specific forms without changing the technical idea or essential characteristics of the present invention. Therefore, it should be understood that the above-described embodiments are illustrative in all respects and not restrictive. For example, each component described as a single component may be implemented in a distributed manner, and likewise, components described as distributed may be implemented in a combined manner.

[0107] The scope of the present invention is indicated by the claims set forth below, and all changes or modifications derived from the meaning and scope of the claims and their equivalent concepts should be interpreted as being included in the scope of the present invention.