Forming nanoparticles into porous structures

Patent metadata

Field	Value
Publication number	US-2020094238-A1
Application number	US-201816139936-A
Country	US
Kind code	A1
Filing date	Sep 24, 2018
Priority date	Sep 24, 2018
Publication date	Mar 26, 2020
Grant date	—

Abstract

Methods for making porous materials having metal alloy nanoparticles formed therein are described herein. By preparing a porous material and delivering the precursor solutions under vacuum, the metal precursors can be uniformly embedded within the pores of the porous material. Once absorption is complete, the porous material can be heated in the presence of one or more functional gases to reduce the metal precursors to metal alloy nanoparticles, and embed the metal alloy nanoparticles inside of the pores. As such, the metal alloy nanoparticles can be formed within the pores, while avoiding surface wetting and absorption problems which can occur with small pores.

First claim

What is claimed is:

1 . A method for forming platinum alloy nanoparticles into porous carbon, comprising:
heating a porous carbon material within a chamber, the porous carbon material having one or more pores; applying a vacuum to the chamber; impregnating the porous carbon material using a platinum precursor and a metal precursor; heating the precursor-impregnated porous carbon material to a functional temperature; and delivering a functional gas to the precursor-impregnated porous carbon material, the platinum precursor and the metal precursors reacting with the functional gas to form platinum alloy nanoparticles within the one or more pores.

2 . The method of claim 1 , further comprising delivering a purge gas prior to heating the porous carbon material to the functional temperature, the purge gas being a gas that is inert with respect to the platinum precursor solution and the metal precursor solution.

3 . The method of claim 1 , wherein the metal precursor comprises platinum, copper, nickel, or combinations thereof.

4 . The method of claim 1 , wherein applying the vacuum creates a pressure within the chamber of less than 500 millibars.

5 . The method of claim 1 , wherein the porous carbon material is a mesoporous carbon.

6 . The method of claim 1 , wherein the functional gas is a gas mixture comprising H 2 and CO.

7 . The method of claim 6 , further comprising delivering the functional gas at a partial pressure ratio of from 1:100 to 1:1 of H 2 to CO, and a volumetric flow rate of from 10 sccm to 1000 sccm.

8 . The method of claim 1 , wherein the functional temperature is from 150° C. to 300° C.

9 . The method of claim 8 , further comprising maintaining the functional temperature for from 1 hour to 5 hours in the presence of the functional gas.

10 . A method for forming platinum alloy particles into porous carbon, comprising:
removing moisture from a porous carbon material within a chamber, the porous carbon material having one or more pores; applying a vacuum to the chamber; delivering one or more precursors to the porous carbon material to impregnate the porous carbon material, the one or more precursors comprising platinum, nickel, and copper; purging the chamber using a purge gas; heating the precursor-impregnated porous carbon material to a functional temperature; and delivering a functional gas to the precursor-impregnated porous carbon material, the one or more precursors reacting with the functional gas to form octahedral platinum alloy nanoparticles within the one or more pores of the porous carbon material.

11 . The method of claim 10 , comprising delivering the precursor solution with agitation.

12 . The method of claim 10 , wherein removing moisture comprises heating the porous carbon material to a first temperature in a controlled atmosphere comprising air, Ar, N 2 , O 2 , or combinations thereof.

13 . The method of claim 10 , wherein applying the vacuum creates a pressure within the chamber of less than 500 millibars.

14 . The method of claim 10 , comprising maintaining the vacuum during the purging of the chamber.

15 . The method of claim 10 , wherein the functional gas is a gas mixture comprising H 2 and CO.

16 . The method of claim 15 , comprising delivering the functional gas at a partial pressure ratio of from 1:100 to 1:1 of H 2 to CO, and a volumetric flow rate of from 10 sccm to 1000 sccm.

17 . The method of claim 10 , wherein the functional temperature is from 150° C. to 300° C.

18 . The method of claim 17 , further comprising maintaining the functional temperature for a time period of from 1 hour to 5 hours in the presence of the functional gas.

19 . A method for forming platinum alloy particles into porous carbon, comprising:
heating a porous carbon material in a chamber to a temperature of from 150° C. to 300° C., for a time period of from 1 hour to 24 hours, in an atmosphere comprising air, Ar, N 2 , O 2 , or combinations thereof, the porous carbon material having one or more pores; reducing pressure within the chamber to less than 500 millibars; delivering one or more precursors to the porous carbon material, the one or more precursors comprising platinum(acac) 2 , copper(acac) 2 , and nickel(acac) 2 , the one or more precursors being dissolved in a volatile solvent; purging the chamber using a purge gas; heating the porous carbon material to a temperature from 150° C. to 300° C. for a period of from 1 hour to 5 hours; and delivering a functional gas to the porous carbon material, the one or more precursors reacting with the functional gas to form octahedral platinum alloy nanoparticles within the one or more pores.

20 . The method of claim 19 , wherein the functional gas is H 2 and CO, delivered at a partial pressure ratio of from 1:100 to 1:1 of H 2 to CO, and a volumetric flow rate of from 10 sccm to 1000 sccm.

Assignees

• Toyota Eng & Mfg North America
• Toyota Motor Co Ltd
• Univ Akron

Inventors

• Zhou Li Qin
• Huang Kan
• Nagai Tomoyuki
• Jia Hongfei
• Kato Hisao
• Shen Xiaochen
• Peng Zhenmeng

Classifications

• B01J37/08

  Heat treatment {(B01J37/0009, B01J37/0018 take precedence)} · CPC title

• B01J37/18

  with gases containing free hydrogen · CPC title

• B01J37/0203

  the impregnation liquid containing organic compounds · CPC title

• B01J23/42

  Platinum · CPC title

• B01J37/0207 Primary

  Pretreatment of the support · CPC title