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A precious metal alloy core-shell catalyst prepared by using an organic reducing agent and its preparation method

A noble metal and catalyst technology, applied in the field of high-performance ultrafine low-Pt core-shell catalyst and its preparation, can solve the problems of high cost and insufficient lifespan

Active Publication Date: 2021-04-27
TSINGHUA UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Pt-based catalysts are considered to have the best catalytic activity for ORR, however, they are costly and have insufficient lifetime

Method used

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  • A precious metal alloy core-shell catalyst prepared by using an organic reducing agent and its preparation method
  • A precious metal alloy core-shell catalyst prepared by using an organic reducing agent and its preparation method
  • A precious metal alloy core-shell catalyst prepared by using an organic reducing agent and its preparation method

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0057] First, 1wt.% AgNO 3 Dilute the solution in 100mL of deionized water, add 0.034g of protective surfactant CTAB and 50mg of loaded carbon carrier XC-72, ultrasonically disperse for 30min, then heat the oil bath to 105°C, add 1wt.% sodium citrate 10mL, carry out Reduction of carboxyl and hydroxyl groups, oil bath reduction temperature 105°C, time 1h; cool down to 60°C, add 0.015mol / L H 2 PtCl 6 3mL, replace at 60°C for 2h to prepare a transition layer; mix 1.2g of ascorbic acid with H 2 PtCl 6 3mL, dissolve and mix with 25mL and add, adjust pH=10 with NaOH, carry out carboxyl and hydroxyl reduction at 60°C for 4h, finally add 0.2gNaBH 4 Mix solution with 0.06g NaOH, stir and age overnight; centrifuge and dry to obtain Ag@Pt / C (60°C) catalyst. The physical characterization of the catalyst is shown in Figures 1-3, and the performance of the catalyst is shown in Figure 4.

[0058] Figure 1 is a low magnification TEM image of the catalyst prepared in Example 1, (a) it c...

Embodiment 2

[0063] First, 1wt.% AgNO 3 Dilute the solution in 100mL of deionized water, add 0.034g of protective surfactant CTAB and 50mg of loaded carbon carrier XC-72, ultrasonically disperse for 30min, then heat the oil bath to 105°C, add 1wt.% sodium citrate 10mL, carry out Reduction of carboxyl and hydroxyl groups, oil bath reduction temperature 105°C, time 1h; maintain 105°C, add 0.015mol / L H2PtCl6 3mL, replace at 105°C for 2h, prepare transition layer; ascorbic acid 1.2g, H 2 PtCl 6 3mL, dissolve and mix with 25mL and add, adjust pH=10 with NaOH, carry out carboxyl and hydroxyl reduction at 105°C for 4h, finally add 0.2gNaBH 4 Mix solution with 0.06g NaOH, stir and age overnight; centrifuge and dry to obtain Ag@Pt / C (60°C) catalyst. Catalyst performance is shown in Figure 5.

[0064] Fig. 5 is a graph showing the electrochemical performance of the catalyst prepared in Example 2 of the present invention. (a) Comparison of CV activity between prepared Ag@Pt / C catalyst and commer...

Embodiment 3

[0066]Electrochemical tests were performed in a three-electrode system to characterize the oxygen reduction activity of the catalysts. The electrolyte solution of this system is 0.1mol L -1 HClO 4 , the counter electrode is a Pt sheet electrode, the reference electrode is a saturated calomel electrode, the cyclic voltammetry test electrolyte solution is saturated with N2, and the test system is Gamry3000; the ORR test solution is saturated with O2. Preparation of the catalytic layer of the rotating disk electrode membrane: 40% Pt / C catalyst: 5mg catalyst, 2.5mL isopropanol, ultrasonication; add 50 μL of 5wt% Nafion solution, ultrasonication, take 3.2 μL of the above dispersed slurry and coat it on a rotating disk electrode The disc electrode surface, as the working electrode. Due to the low loading of the Ag@Pt / C catalyst, preparation of the membrane catalyst layer: 5mg catalyst, 2.5mL isopropanol, ultrasonication; add 50μL of 5wt% Nafion solution, ultrasonication, take 6.4μ...

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Abstract

The invention belongs to the technical field of fuel cells and electrochemical catalysis, and in particular relates to a high-performance ultrafine low-Pt core-shell catalyst prepared by an organic reduction method and a preparation method thereof. The invention provides a noble metal alloy core-shell catalyst, which has a carbon atomic percentage of 90-96 at.%, an O element atomic percentage of 2-7% at.%, a surface Pt loading of 0.1-2 at.%, and a metal particle size of 0.5-5nm. . The invention prepares a low-platinum-shell-core alloy catalyst by controlling the reduction of organic carboxyl and hydroxyl reducing agents, and exhibits excellent oxygen reduction activity and electrocatalytic performance under acidic conditions.

Description

technical field [0001] The invention belongs to the technical field of fuel cells and electrochemical catalysis, and in particular relates to a high-performance ultrafine low-Pt core-shell catalyst prepared by an organic reduction method and a preparation method thereof. Background technique [0002] The proton exchange membrane fuel cell is a reaction device that directly converts the chemical energy of the fuel into electrical energy. It is the key technology for the development of new energy vehicles. An important direction for the development of new energy technologies (Zipeng Zhao et al, Adv. Mater., 2019). Fuel cells include electrodes, electrolytes, collector materials, and external circuits. Electrodes are where the electrochemical reactions of fuel cells occur, including noble metal catalysts and proton conductors. Currently, high-load Pt / C catalysts are mainly used (Meixia Wu et al., Electrochimica Acta, 2019). As the core material of the fuel cell, the catalyst ...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): B01J23/52B01J37/16B01J37/02H01M4/88H01M4/92B82Y30/00B82Y40/00
CPCB01J23/52B01J37/16B01J37/0215H01M4/926H01M4/8825B82Y30/00B82Y40/00B01J35/397B01J35/23B01J35/33Y02E60/50
Inventor 赵卿王诚王建龙孙连国张泽坪
Owner TSINGHUA UNIV
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