Preparation method of alumina supported cerium oxide powder material

Abstract

The present invention discloses a preparation method of an alumina supported cerium oxide powder material. A cerium organometallic precursor is effectively decomposed into CeO.sub.2 nanoparticles at 500-700 C. in an oxygen atmosphere condition by using a chemical vapor deposition method, and the CeO.sub.2 nanoparticles are evenly dispersed on an Al.sub.2O.sub.3 support. The decomposition of the CeO.sub.2 precursor is accelerated by changing experimental parameters of reaction between organic materials and oxygen, so as to control the size and microstructure of powder, thereby achieving the preparation and even dispersion of cerium oxide nanoparticles, and avoiding the problem of generation of toxic waste liquor during reaction. The method of the present invention is simple, has a short preparation period, and the cerium oxide nanoparticles prepared are evenly dispersed, can be used as catalytic materials and functional materials, and have a broad application prospect in multiple fields.

Claims

1. A method of preparing an alumina supported cerium oxide powder material, comprising: (1) providing a cerium organometallic precursor as a CeO.sub.2 material, and heating the cerium organometallic precursor in a feed vaporizer to vaporize, wherein a heating temperature range is 100 to 300 C.; (2) pretreating Al.sub.2O.sub.3 powder by drying and sieving, and then placing the pretreated Al.sub.2O.sub.3 powder into a chemical vapor deposition reaction chamber, vacuumizing to 5 to 20 Pa, and preheating, wherein a preheating temperature is 500 to 800 C.; (3) feeding a mixed gas of oxygen and argon gas, and vaporized CeO.sub.2 material into a rotating reactor, and conducting rotary chemical vapor deposition under a high temperature to make the cerium organometallic precursor be decomposed into CeO.sub.2 and deposited on the Al.sub.2O.sub.3 powder; (4) after completing the reaction, stopping the rotation of the reaction chamber, closing a valve, cooling to a room temperature, and removing the coated powder; and (5) grinding and sieving the powder obtained by step (4).

2. The method according to claim 1, wherein in step (1), the cerium organometallic precursor is any one of Ce(DPM).sub.4, cerium isooctanoate, Ce(C.sub.5H.sub.5).sub.3, or cerium acetate.

3. The method according to claim 1, wherein in step (2), the average particle size of the Al.sub.2O.sub.3 powder is 0.1 to 100 m, and the purity of the Al.sub.2O.sub.3 powder is no less than 95%.

4. The method according to claim 1, wherein in step (2), the temperature rise rate of the preheating process is 2 to 10 C./min.

5. The method according to claim 1, wherein in step (3), the condition of the rotary chemical vapor deposition is: a reaction temperature is 600 to 800 C., the rotating speed of the chemical vapor deposition reaction chamber is 20 to 60 rpm, and a thermal insulation reaction is conducted for 0.5 to 4 h, wherein the gas flow of argon gas is 80 to 100 sccm, and the gas flow of oxygen is 10 to 100 sccm.

6. The method according to claim 1, wherein the total pressure of the fed mixed gas of oxygen and argon gas is 200 to 1000 Pa, and the partial pressure of oxygen is 50 to 200 Pa.

7. The method according to claim 1, wherein in step (2), the temperature of pretreating the Al.sub.2O.sub.3 powder for drying is 80 to 100 C., the size of a sieve pore for sieving the Al.sub.2O.sub.3 powder is 50 to 200 meshes, and the Al.sub.2O.sub.3 powder is sieved three times.

8. The according to claim 1, wherein in step (5), the size of a sieve pore for sieving the powder is 50 to 200 meshes, and the powder is sieved three times.

9. An alumina supported cerium oxide powder material prepared by the preparation method according to claim 1, comprising CeO.sub.2 nanoparticles on a surface of the Al.sub.2O.sub.3 powder; wherein: the average particle size of the Al.sub.2O.sub.3 powder is 0.1 to 100 m, and the purity of the Al.sub.2O.sub.3 powder is no less than 95%; the CeO.sub.2 nanoparticles have an average particle size of 6-13 nm; the CeO.sub.2 nanoparticles are evenly distributed on the surface of the Al.sub.2O.sub.3 powder; and the CeO.sub.2 nanoparticles are included at 0.5-5.2 wt % of the alumina supported cerium oxide powder material.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 is a transmission electron microscope of CeO.sub.2 nanoparticles obtained under experimental parameters according to embodiment 3; and

(2) FIG. 2 is an X ray diffraction pattern of a composite powder material obtained under the experimental parameters according to the embodiment 3.

DETAILED DESCRIPTION

(3) The following are merely preferred embodiments of the invention, which are intended to be illustrative of the invention only, rather than to limit the invention, and improvements made from this description shall all fall within the scope of protection as defined by the appended claims of the invention.

Embodiment 1

(4) The present invention provides a preparation method of an alumina supported cerium oxide powder material, comprising the following steps of:

(5) (1) using 1 g Ce(DPM).sub.4 as an organic material and heating the material in an vaporizer to 250 C.;

(6) (2) drying 5 g Al.sub.2O.sub.3 powder (the average particle size of the Al.sub.2O.sub.3 powder was 100 m, and the purity of the powder was no less than 95%) for 2 h under 80 C., then placing the treated Al.sub.2O.sub.3 powder into a chemical vapor deposition reaction chamber, vacuumizing to 7 Pa, and warming up to 500 C. with a preheating temperature rise rate of 10 C./min;

(7) (3) feeding mixed gas of oxygen, argon gas and vaporized materials into a rotating reactor, wherein the gas flow of argon gas was 100 sccm, and the gas flow of oxygen was 10 sccm, then adjusting the pressure in the reaction chamber, wherein the total pressure was 200 Pa, and the partial pressure of oxygen was 50 Pa; during coating, the temperature was 600 C., the rotating speed of the reactor was 45 rpm, and thermal insulation was conducted for 0.5 h, so that Ce(DPM).sub.4 was decomposed and deposited on the Al.sub.2O.sub.3 powder;

(8) (4) after completing the reaction, stopping the rotation of the reaction chamber, closing a valve, cooling to a room temperature, and removing the coated powder; and

(9) (5) grinding and sieving the powder obtained by step (4).

(10) The removed CeO.sub.2Al.sub.2O.sub.3 composite material was weighed, and analyzed and viewed by means of X ray diffraction, transmission electron microscope and energy spectrum, etc. The content by weight of CeO.sub.2 in the composite powder obtained was 0.5 wt %, the average particle size of CeO.sub.2 was 8 nm, and CeO.sub.2 was evenly distributed.

Embodiment 2

(11) The present invention provides a preparation method of an alumina supported cerium oxide powder material, comprising the following steps of:

(12) (1) using 3 g Ce(DPM).sub.4 as an organic material and heating the material in an vaporizer to 100 C.;

(13) (2) drying 5 g Al.sub.2O.sub.3 powder (the average particle size of the Al.sub.2O.sub.3 powder was 50 m, and the purity of the powder was no less than 95%) for 2 h under 80 C., then placing the treated Al.sub.2O.sub.3 powder into a chemical vapor deposition reaction chamber, vacuumizing to 5 Pa, and warming up to 600 C. with a preheating temperature rise rate of 2 C./min;

(14) (3) feeding mixed gas of oxygen, argon gas and vaporized materials into a rotating reactor, wherein the gas flow of argon gas was 100 sccm, and the gas flow of oxygen was 10 sccm, then adjusting the pressure in the reaction chamber, wherein the total pressure was 500 Pa, and the partial pressure of oxygen was 100 Pa; during coating, the temperature was 600 C., the rotating speed of the reactor was 45 rpm, and thermal insulation was conducted for 1 h, so that Ce(DPM).sub.4 was decomposed and deposited on the Al.sub.2O.sub.3 powder;

(15) (4) after completing the reaction, stopping the rotation of the reaction chamber, closing a valve, cooling to a room temperature, and removing the coated powder; and

(16) (5) grinding and sieving the powder obtained by step (4).

(17) The removed CeO.sub.2Al.sub.2O.sub.3 composite material was weighed, and analyzed and viewed by means of X ray diffraction, transmission electron microscope and energy spectrum, etc. The content by weight of CeO.sub.2 in the composite powder obtained was 1.2 wt %, the average particle size of CeO.sub.2 was 6 nm, and CeO.sub.2 was evenly distributed.

Embodiment 3

(18) The present invention provides a preparation method of an alumina supported cerium oxide powder material, comprising the following steps of:

(19) (1) using 10 g Ce(DPM).sub.4 as an organic material and heating the material in an vaporizer to 100 C.;

(20) (2) drying 5 g Al.sub.2O.sub.3 powder (the average particle size of the Al.sub.2O.sub.3 powder is 10 m, and the purity of the powder is no less than 95%) for 2 h under 80 C., pretreating the powder by a 100-mesh sieve for three times, then placing the treated Al.sub.2O.sub.3 powder into a chemical vapor deposition reaction chamber, vacuumizing to 5 Pa, and warming up to 600 C. with a preheating temperature rise rate of 5 C./min;

(21) (3) feeding mixed gas of oxygen, argon gas and vaporized materials into a rotating reactor, wherein the gas flow of argon gas was 100 sccm, and the gas flow of oxygen was 10 sccm, then adjusting the pressure in the reaction chamber, wherein the total pressure was 1000 Pa, and the partial pressure of oxygen was 300 Pa; during coating, the temperature was 800 C., the rotating speed of the reactor was 45 rpm, and thermal insulation was conducted for 2 h, so that Ce(DPM).sub.4 was decomposed and deposited on the Al.sub.2O.sub.3 powder;

(22) (4) after completing the reaction, stopping the rotation of the reaction chamber, closing a valve, cooling to a room temperature, and removing the coated powder; and

(23) (5) grinding and sieving the powder obtained by step (4).

(24) The removed CeO.sub.2Al.sub.2O.sub.3 composite material was weighed, and analyzed and viewed by means of X ray diffraction, transmission electron microscope and energy spectrum, etc. The results are shown in FIG. 1 and FIG. 2, where FIG. 1 is a transmission electron microscope of CeO.sub.2 nanoparticles; and FIG. 2 is an X ray diffraction pattern of the composite powder material obtained. The content by weight of CeO.sub.2 in the composite powder obtained was 5.2 wt %, the average particle size of CeO.sub.2 was 13 nm, and CeO.sub.2 was evenly distributed.

Embodiment 4

(25) The present invention provides a preparation method of an alumina supported cerium oxide powder material, comprising the following steps of:

(26) (1) using 10 g Ce(DPM).sub.4 as an organic material and heating the material in an vaporizer to 300 C.;

(27) drying 5 g Al.sub.2O.sub.3 powder (the average particle size of the Al.sub.2O.sub.3 powder is 1 m, and the purity of the powder is no less than 95%) for 2 h under 80 C., pretreating the powder by a 200-mesh sieve for three times, then placing the treated Al.sub.2O.sub.3 powder into a chemical vapor deposition reaction chamber, vacuumizing to 10 Pa, and warming up to 700 C. with a preheating temperature rise rate of 5 C./min;

(28) (3) feeding mixed gas of oxygen, argon gas and vaporized materials into a rotating reactor, wherein the gas flow of argon gas was 100 sccm, and the gas flow of oxygen was 10 sccm, then adjusting the pressure in the reaction chamber, wherein the total pressure was 800 Pa, and the partial pressure of oxygen was 200 Pa; during coating, the temperature was 700 C., the rotating speed of the reactor was 45 rpm, and thermal insulation was conducted for 2 h, so that Ce(DPM).sub.4 was decomposed and deposited on the Al.sub.2O.sub.3 powder;

(29) (4) after completing the reaction, stopping the rotation of the reaction chamber, closing a valve, cooling to a room temperature, and removing the coated powder; and

(30) (5) grinding and sieving the powder obtained by step (4).

(31) The removed CeO.sub.2Al.sub.2O.sub.3 composite material was weighed, and analyzed and viewed by means of X ray diffraction, transmission electron microscope and energy spectrum, etc. The content by weight of CeO.sub.2 in the composite powder obtained was 4.5 wt %, the average particle size of CeO.sub.2 was 10 nm, and CeO.sub.2 was evenly distributed.

Embodiment 5

(32) The present invention provides a preparation method of an alumina supported cerium oxide powder material, comprising the following steps of:

(33) using 8 g Ce(DPM).sub.4 as an organic material and heating the material in an vaporizer to 200 C.;

(34) drying 5 g Al.sub.2O.sub.3 powder (the average particle size of the Al.sub.2O.sub.3 powder is 0.1 m, and the purity of the powder is no less than 95%) for 2 h under 80 C., pretreating the powder by a 100-mesh sieve and a 300-mesh sieve for three times, then placing the treated Al.sub.2O.sub.3 powder into a chemical vapor deposition reaction chamber, vacuumizing to 8 Pa, and warming up to 650 C. with a preheating temperature rise rate of 4 C./min;

(35) (3) feeding mixed gas of oxygen, argon gas and vaporized materials into a rotating reactor, wherein the gas flow of argon gas was 100 sccm, and the gas flow of oxygen was 10 sccm, then adjusting the pressure in the reaction chamber, wherein the total pressure was 800 Pa, and the partial pressure of oxygen was 300 Pa; during coating, the temperature was 650 C., the rotating speed of the reactor was 45 rpm, and thermal insulation was conducted for 2 h, so that Ce(DPM).sub.4 was decomposed and deposited on the Al.sub.2O.sub.3 powder;

(36) (4) after completing the reaction, stopping the rotation of the reaction chamber, closing a valve, cooling to a room temperature, and removing the coated powder; and

(37) (5) grinding and sieving the powder obtained by step (4).

(38) The removed CeO.sub.2Al.sub.2O.sub.3 composite material was weighed, and analyzed and viewed by means of X ray diffraction, transmission electron microscope and energy spectrum, etc. The content by weight of CeO.sub.2 in the composite powder obtained was 4.0 wt %, the average particle size of CeO.sub.2 was 9 nm, and CeO.sub.2 was evenly distributed.

(39) The foregoing description of the disclosed embodiments enables those skilled in the art to make or use the present invention. Various modifications to these embodiments will be apparent to those skilled in the art, and the generic principles defined herein may be embodied in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention will not to be limited to the embodiments shown herein, but is to be in conformity with the widest scope consistent with the principles and novel features disclosed herein.