PtCu/C Materials Doped with Different Amounts of Gold as the Catalysts of Oxygen Electroreduction and Methanol Electroox
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/C Materials Doped with Different Amounts of Gold as the Catalysts of Oxygen Electroreduction and Methanol Electrooxidation S. V. Belenova, *, V. S. Men’shchikova, A. Yu. Nikulina, and N. M. Novikovskiia aSouthern
Federal University, Faculty of Chemistry, Rostov-on-Don, 344006 Russia *е-mail: [email protected]
Received June 5, 2019; revised December 13, 2019; accepted December 13, 2019
Abstract—The effect of the amount of gold used as the dopant of PtCu nanoparticles on the structure of PtCuAu/Cu catalysts and their activity in the reactions of oxygen reduction and methanol electrooxidation is studied. The PtCuAu/C materials containing from 3 to 20% of gold are prepared by galvanic displacement of copper atoms by gold atoms on the surface of already prepared PtCu nanoparticles. The addition of 5 at % Au to the composition of nanoparticles doubles their activity in the methanol oxidation and increases their activity in the oxygen reduction by a factor of 1.7 as compared with the commercial Pt/C material JM40. This study confirms that multicomponent platinum-containing nanoparticles supported by a highly disperse carbon material and having gold atoms deposited on their surface show promise as the efficient catalysts for the methanol fuel cells. In contrast, the materials containing 10 at % Au and more are characterized by the presence of gold nanoparticles on the carbon support surface and exhibit the lower catalytic activity as compared with those containing less amounts of gold. Keywords: nanoparticles, doping with gold, electrocatalysts, oxygen reduction reaction, methanol electrooxidation DOI: 10.1134/S1023193520080029
INTRODUCTION Fuel cells (FCs) with proton-exchange membranes are among the most promising energy sources used in vehicles and as portable power-supplying devices because of their high energy density and the low level of harmful emissions. For the efficient operation of a FC, one has to use the catalysts capable of accelerating the reactions of fuel oxidation on the anode and oxygen electroreduction on the cathode. Platinum is known as the best catalyst for FC [1, 2]; however, the use of pure Pt for electrooxidation of small organic molecules, e.g., formic acid, methanol, and ethanol is unpractical because Pt regions are being deactivated during the oxidation by CO. The latter is chemisorbed on the surface thus contaminating the catalyst and decreasing its activity [3]. One of the ways to enhance the activity of a Pt catalyst in oxidation of organic molecules is its doping with various metals: Ru [4], Ni [5], Co [5, 6], Cu [7], etc. The presence of the second metal makes easier the oxidation of CO chemisorbed on the platinum surface [8] and also enhances the catalytic properties of materials. However, the functioning of a catalyst is accompanied by dissolution of the nonprecious metal, which results in poisoning of the proton-exchange membrane and fast degradation of specific characteristics of the FC. One of possible
solutions of this problem may be the introduction of another inert metal tha
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