METHOD FOR PREPARATION OF OXIDE SUPPORT-NANOPARTICLE COMPOSITES

Abstract

There is provided a method for preparation of oxide support-nanoparticle composites, in which metal nanoparticles decorate with uniform size and distribution on the surface of an oxide support, and thus, high performance oxide support-nanoparticle composites that can be applied in the fields of heterogeneous catalysis can be provided.

Claims

1. A method for preparation of oxide support-nanoparticle composites, comprising the steps of: preparing a support consisting of perovskite oxide represented by the following Chemical Formula 1 (step 1); and heat treating the support at 350 to 900° C. under an oxygen partial pressure of 10.sup.−35 to 10.sup.−12 atm to form nanoparticles on the support (step 2):
A.sub.xB.sub.1-yB′.sub.yO.sub.3  [Chemical Formula 1] in Chemical Formula 1, x is 0.9 to 1, y is 0.05 to 0.25, A is one or more selected from the group consisting of Pr, Nd, Ca, Sr, Ba, and La, B is Zr, Cr, Al, Ti, Mn, Fe, or Co, and B′ is Mn, Fe, Co, Ni, Cu, Pd, Ir, Ru, or Pt, with the proviso that B and B′ are not the same.

2. The method for preparation of oxide support-nanoparticle composites according to claim 1, wherein B is Ti.

3. The method for preparation of oxide support-nanoparticle composites according to claim 1, wherein the heat treatment time of step 2 is 2 hours to 10 hours.

4. The method for preparation of oxide support-nanoparticle composites according to claim 1, wherein the heat treatment of step 2 comprises raising a temperature from room temperature to a temperature of 350 to 900° C. at a temperature rise speed of 1 to 50° C./min.

5. The method for preparation of oxide support-nanoparticle composites according to claim 1, wherein the heat treatment of step 2 comprises raising a temperature from room temperature to a temperature of 650 to 800° C. at a temperature rise speed of 1 to 50° C./min.

6. The method for preparation of oxide support-nanoparticle composites according to claim 1, wherein the average diameter of the nanoparticles is 5 nm to 100 nm.

7. The method for preparation of oxide support-nanoparticle composites according to claim 1, wherein the average diameter of the nanoparticles is 7 nm to 60 nm.

8. The method for preparation of oxide support-nanoparticle composites according to claim 1, wherein the nanoparticles exist at a density of 0.1/um.sup.2 to 600/um.sup.2 on the oxide support-nanoparticle composite.

9. The method for preparation of oxide support-nanoparticle composites according to claim 1, wherein the metal nanoparticles consist of the B′ elements of Chemical Formula 1.

10. An oxide support-nanoparticle composite prepared by the method according to claim 1.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0039] FIG. 1 shows the results of observation according to Experimental Example 1 of the invention. Further, (g) of FIG. 1 graphically shows the results of Experimental Example 1.

[0040] FIG. 2 shows the results of observation according to Experimental Example 2.

[0041] FIG. 3 shows the results of observation according to Experimental Example 3.

[0042] FIG. 4 shows the results of observation according to Experimental Example 4.

DETAILED DESCRIPTION OF THE EMBODIMENTS

[0043] Hereinafter, preferable examples are presented for better understanding of the invention. However, these examples are presented only as illustrations of the invention, and the invention is not limited thereby.

Experimental Example 1

[0044] After loading a single phase Sr.sub.0.98Ti.sub.0.95Co.sub.0.05O.sub.3 thin film in a tube furnace, a gas with an appropriate H.sub.2/H.sub.2O ratio was flowed so as to set up each oxygen partial pressure (10.sup.−26 atm and 10.sup.−23 atm) at each set up temperature (700° C., 750° C., and 800° C.). While confirming oxygen partial pressure with an oxygen partial pressure sensor in real time, after the gas reached a steady-state, the temperature was raised from room temperature (25° C.) to the set up temperature at 5° C./min. Subsequently, the surface of each thin film was observed with a SEM, and the results are shown in FIG. 1.

Experimental Example 2

[0045] After loading a single phase Sr.sub.0.98Ti.sub.0.95Co.sub.0.05O.sub.3 thin film in a tube furnace, 100% H.sub.2 gas was flowed so as to give sufficient driving force with gas. Herein, an oxygen partial pressure was confirmed to be about 10.sup.−29 atm. Subsequently, the temperature was raised from room temperature (25° C.) to 700° C. at each set up temperature rise speed (1° C./min, 5° C./min, and 50° C./min). Subsequently, the surface of each thin film was observed with a SEM, and the results are shown in FIG. 2.

Experimental Example 3

[0046] After loading each perovskite thin film doped with Mn, Fe, Ni, or Cu (Sr.sub.0.98Ti.sub.0.95Mn.sub.0.05O.sub.3, Sr.sub.0.98Ti.sub.0.95Fe.sub.0.05O.sub.3, Sr.sub.0.98Ti.sub.0.95Ni.sub.0.05O.sub.3, Sr.sub.0.98Ti.sub.0.95Cu.sub.0.05O.sub.3) in a tube furnace, gas with an appropriate H.sub.2/H.sub.2O ratio was flowed so as to set up each oxygen partial pressure (10.sup.−26 atm, 10.sup.−23 atm, and 10.sup.−20 atm) at 700° C. While confirming oxygen partial pressure with an oxygen partial pressure sensor in real time, after gas reached a steady-state, the temperature was raised from room temperature (25° C.) to 700° C. at 5° C./min. Subsequently, the surface of each thin film was observed with a SEM, and the results are shown in FIG. 3.

Experimental Example 4

[0047] After loading each perovskite thin film to which Ba and Co were added (STC: SrTi.sub.0.75C.sub.0.25O.sub.3, and BSTC: Ba.sub.0.05Sr.sub.0.95Ti.sub.0.75Co.sub.0.25O.sub.3) in a tube furnace, gas consisting of 5 vol % H.sub.2+95 vol % Ar was flowed to make a steady-state. Herein, the oxygen partial pressure was confirmed to be ˜10.sup.−30 atm. Subsequently, heat treatment was conducted by raising the temperature from room temperature (25° C.) to 500° C. at 5° C./min.

[0048] The above-prepared samples were loaded in a tube furnace connected with a mass spectroscope, and while flowing gas consisting of 1 vol % CO, 4 vol % O.sub.2, and 95 vol % Ar, the degree of CO.sub.2 formation was measured by mass spectroscopy according to temperature, and the results are shown in FIG. 4.