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.−26 to 10.sup.−17 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′ element of Chemical Formula 1.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) 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.

(2) FIG. 2 shows the results of observation according to Experimental Example 2.

(3) FIG. 3 shows the results of observation according to Experimental Example 3.

(4) FIG. 4 shows the results of observation according to Experimental Example 4.

DETAILED DESCRIPTION OF THE EMBODIMENTS

(5) 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

(6) 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

(7) 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

(8) 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

(9) 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.

(10) 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.