CN101785999B

CN101785999B - Preparation method of electro-catalyst Pt1Bi1 intermetallic compounds used for fuel batteries

Info

Publication number: CN101785999B
Application number: CN2010101087409A
Authority: CN
Inventors: 李翔; 夏定国; 陈戈; 刘淑珍; 张丽娟
Original assignee: Beijing University of Technology
Current assignee: Beijing University of Technology
Priority date: 2010-02-05
Filing date: 2010-02-05
Publication date: 2012-05-30
Anticipated expiration: 2030-02-05
Also published as: CN101785999A

Abstract

The invention discloses a preparation method of electro-catalyst Pt1Bi1 intermetallic compounds used for proton exchange membrane fuel batteries, which comprises two steps: 1) adding 0.1 mmol bismuth-containing precursors, 0.1 mmol platinum-containing precursors and carbon powder into 200 ml 1 mol L<-1> hydrochloric acid solution according to the atomic ratio of platinum to bismuth of 1/1, regulating the pH value to 3 under the water bath agitation through 5 mol L<-1> sodium hydroxide solution, then, adding reducing agents for reaction for 10 hours at 90 DEG C, and filtering obtained materials to obtain precursors of the Pt1Bi1 intermetallic compounds; and 2) carrying out heat treatment on the precursors obtained in the first step in reducing atmosphere at the lower temperature between 300 and 600 DEG C for 2 to 6 hours to obtain the Pt1Bi1 intermetallic compound electro-catalyst. The grains of the Pt1Bi1 intermetallic compounds prepared by the method of the invention have the grain diameter about 3 nm, and have good methylismus-resistance oxygen reduction activity and electro-catalysis oxidation oxidization activity. The method has simple preparation, and is applicable to large-scale preparation.

Description

A kind of electrocatalyst for fuel cell Pt 1Bi 1The preparation method of intermetallic compound

Technical field

The present invention relates to a kind of electrocatalyst for fuel cell Pt ₁Bi ₁The preparation method of intermetallic compound belongs to fuel cell material science and technology field and electro-catalysis field.

Background technology

Fuel cell is a kind ofly to convert chemical energy the device of electric energy into, because it does not receive the restriction of Carnot cycle, energy conversion efficiency is high, and environmental friendliness and received extensive concern, and it is considered to the generation mode of first-selected high-efficiency cleaning of 21 century.

Different according to the electrolyte of being selected for use; Fuel cell can be divided into five types (alkaline fuel cell, Proton Exchange Membrane Fuel Cells, phosphoric acid fuel cell, molten carbonate fuel cell, SOFCs); Wherein, but characteristics such as the PEM membrane cell is owing to having that room temperature starts fast, the life-span long, specific power and specific energy height are especially suitable for use as the power supply of electric automobile and portable electric appts.

At present; The eelctro-catalyst that Proton Exchange Membrane Fuel Cells uses mainly contains two kinds of Pt/C and PtRu; Because Pt costs an arm and a leg and resource-constrained; Therefore desire realizes the Proton Exchange Membrane Fuel Cells commercialization, must further reduce the use amount of platinum and improve its catalytic performance, and Pt base alloying is wherein a kind of main selection.One type of intermetallic compound in the Pt base alloy is owing to have orderly structure and other characteristics and have better catalytic selectivity and catalytic activity and stability than other unordered Pt base solid solution phase alloys.

Summary of the invention

The purpose of this invention is to provide a kind of used in proton exchange membrane fuel cell eelctro-catalyst Pt ₁Bi ₁The preparation method of intermetallic compound.

The present invention proposes Pt ₁Bi ₁The preparation method of intermetallic compound, technical scheme were divided into for two steps:

1) atomic ratio by platinum and bismuth is that 1: 1 each 0.1mmol of presoma and carbon dust with bismuth-containing presoma and platiniferous add 200mL 1mol L ^-1Hydrochloric acid solution in, pass through 5molL under the stirring in water bath ^-1Sodium hydroxide solution is regulated pH to 3, adds reducing agent then, and 90 ℃ of following reactions are filtered after 10 hours and obtained Pt ₁Bi ₁The intermetallic compound presoma;

2) with 1) presoma that makes in the process under reducing atmosphere low temperature 300-600 ℃ obtain intermetallic compound Pt after heat treatment 2-6 hour ₁Bi ₁Eelctro-catalyst.

Above-mentioned bismuth-containing presoma is bismuth chloride or bismuth nitrate; The platiniferous presoma is chloroplatinic acid, platinum tetrachloride; The quality of carbon dust prepares in the catalyst carrying capacity of platinum according to need and confirms that reducing agent is ortho phosphorous acid sodium dihydrogen or sodium borohydride, and the mol ratio that its mol ratio that adds ortho phosphorous acid sodium dihydrogen and metallic atom total amount is 100-120 or sodium borohydride and metallic atom total amount is 50-60; Heat treated reducing atmosphere is that hydrogen volume compares the distribution greater than 2%; Another component in the distribution is an inert atmosphere, for nitrogen or argon gas, like 95%Ar+5%H ₂

The prepared Pt that obtains of the present invention ₁Bi ₁The intermetallic compound particle particle diameter is about 3nm, and hydrogen reduction activity and catalytic oxidation formic acid with fine anti methanol toxication are active, and this method preparation is simple, is fit to mass preparation.

Description of drawings

Fig. 1 is the present invention's " two step method " preparation electrocatalyst for fuel cell Pt ₁Bi ₁The flow chart of intermetallic compound;

The electrocatalyst for fuel cell intermetallic compound Pt of Fig. 2 for making among the embodiment 1 ₁Bi ₁X-ray diffractogram;

The electrocatalyst for fuel cell intermetallic compound Pt of Fig. 3 for making among the embodiment 2 ₁Bi ₁X-ray diffractogram;

The electrocatalyst for fuel cell intermetallic compound Pt that Fig. 4 makes for embodiment 1 ₁Bi ₁The projection electromicroscopic photograph;

The catalyst for fuel cell intermetallic compound Pt that Fig. 5 makes for embodiment 1 ₁Bi ₁At 0.5mol L-1 H ₂SO ₄In the electrochemistry cyclic voltammetry curve, wherein 1 is nitrogen, 2 is oxygen.

Fig. 6 is the intermetallic compound Pt that the embodiment of the invention 1 and embodiment 2 make ₁Bi ₁At 0.5mol L ^-1H ₂SO ₄+ 0.5mol L ^-1Electrochemistry cyclic voltammetry curve among the HCOOH, wherein 1 is the cyclic voltammetry curve of

embodiment

1,2 is the cyclic voltammetry curve of embodiment 2.

The specific embodiment

Embodiment 1

Building-up process is referring to Fig. 1: with 51.8mg chloroplatinic acid (H ₂PtCl ₆6H ₂O) and 48.5mg bismuth nitrate (Bi (NO ₃) ₃5H ₂O) add 200mL 1mol L ^-1In the hydrochloric acid, wait to dissolve the back and add 50mg carbon dust (Vulcan XC-72), under 90 ℃ of water bath with thermostatic control stirring condition, use 5mol L ^-1NaOH regulates pH to 3 back and adds inferior sodium phosphate 3g, reacts that suction filtration goes out sample after 10 hours, and drying is placed on the mixed atmosphere (95%Ar+5%H with reproducibility ₂) in 350 ℃ of heat treatments after 3 hours Compound P t between carbon-supported metal ₁Bi ₁Eelctro-catalyst.Its X-ray diffraction photo is as shown in Figure 2, and the projection electron microscope photo is as shown in Figure 4.With Compound P t between the carbon-supported metal of gained ₁Bi ₁Eelctro-catalyst is processed working electrode, adopts traditional three-electrode system, and standard hydrogen electrode is a reference electrode, and the glass carbon plate carries out electro-chemical test as auxiliary electrode, and Fig. 5 has provided it at 0.5mol L-1H ₂SO ₄Cyclic voltammetry curve under middle nitrogen saturated (1 among Fig. 5) and oxygen saturated (2 among Fig. 5) condition, sweep speed is 20mV s ^-1, 1 has provided it at 0.5mol L-1H among Fig. 6 ₂SO ₄Cyclic voltammetry curve among the+0.5MHCOOH, sweep speed are 50mV s ^-1

Embodiment 2

Building-up process is referring to Fig. 1: with 51.8mg chloroplatinic acid (H ₂PtCl ₆6H ₂O) and 48.5mg bismuth nitrate (Bi (NO ₃) ₃5H ₂O) add 200mL 1mol L ^-1In the hydrochloric acid, wait to dissolve the back and add 50mg carbon dust (Vulcan XC-72), under 90 ℃ of water bath with thermostatic control stirring condition, use 5mol L ^-1NaOH regulates pH to 3 back and adds inferior sodium phosphate 3g, reacts that suction filtration goes out sample after 10 hours, and drying is placed on the mixed atmosphere (95%Ar+5%H with reproducibility ₂) in 500 ℃ of heat treatments after 3 hours Compound P t between carbon-supported metal ₁Bi ₁Eelctro-catalyst.X-ray diffraction photo such as Fig. 3 show.2 have provided the L at 0.5mol among Fig. 6 ^-1H ₂SO ₄Cyclic voltammetry curve among the+0.5MHCOOH, sweep speed are 50mV s ^-1

Embodiment 3

Building-up process is referring to Fig. 1: with 34.0mg platinum tetrachloride (PtCl ₄) and 31.5mg bismuth chloride (BiCl ₃) adding 200mL 1mol L ^-1In the hydrochloric acid, wait to dissolve the back and add 50mg carbon dust (VulcanXC-72), under 90 ℃ of water bath with thermostatic control stirring condition, use 5mol L ^-1NaOH regulates pH to 3 back and adds sodium borohydride (NaBH ₄) 0.4g, react that suction filtration goes out sample after 10 hours, drying is placed on the mixed atmosphere (95%Ar+5%H with reproducibility ₂) in 600 ℃ of heat treatments after 3 hours Compound P t between carbon-supported metal ₁Bi ₁Eelctro-catalyst.

Claims

1. used in proton exchange membrane fuel cell eelctro-catalyst Pt ₁Bi ₁The preparation method of intermetallic compound is characterized in that, may further comprise the steps:

1) atomic ratio by platinum and bismuth is that 1: 1 each 0.1mmol of presoma and carbon dust with bismuth-containing presoma and platiniferous add 200mL 1mol L ^-1Hydrochloric acid solution in, under the stirring in water bath through 5mol L ^-1Sodium hydroxide solution is regulated pH to 3, adds reducing agent then, and 90 ℃ of following reactions are filtered after 10 hours and obtained Pt ₁Bi ₁The intermetallic compound presoma;

2) with 1) presoma that makes in the process under reducing atmosphere low temperature 300-600 ℃ obtain intermetallic compound Pt after heat treatment 2-6 hour ₁Bi ₁Eelctro-catalyst;

Said reducing agent is ortho phosphorous acid sodium dihydrogen or sodium borohydride; Said reducing atmosphere is a hydrogen volume

Compare the distribution greater than 2%, another component in the distribution is an inert atmosphere.

2. according to the preparation method of claim 1, it is characterized in that said bismuth-containing presoma is bismuth chloride or bismuth nitrate.

3. according to the preparation method of claim 1, it is characterized in that said platiniferous presoma is chloroplatinic acid, platinum tetrachloride.

4. according to the preparation method of claim 1, it is characterized in that the mol ratio of ortho phosphorous acid sodium dihydrogen and metallic atom total amount is 100-120.

5. according to the preparation method of claim 1, it is characterized in that the mol ratio of sodium borohydride and metallic atom total amount is 50-60.