Unsupported Cu-Pt Core-Shell Nanoparticles: Oxygen Reduction Reaction (ORR) Catalyst with Better Activity and Reduced Precious Metal Content

Abstract

An unsupported Cu-Pt core-shell catalyst is prepared by a transmetalation reaction between copper and Pt 2+ ions, and a Cu-Pt bimetallic alloy catalyst by a simultaneous reduction reaction. Both catalysts are subjected to electrochemical leaching without further treatment and their electrochemical characteristics and ORR activities are compared to that of a standard Pt black catalyst. Potential cycling in 0.1 M HClO 4 and 0.5 M H 2 SO 4 shows that the core-shell catalyst is highly stable and the electrochemical features show that it is purely Pt on the catalyst surface. The electrochemical surface area of the Cu-Pt core-shell catalyst is much higher than that of the Pt black. When the Pt loading on the electrode is increased with Pt black catalyst to match its geometric electrochemical surface area (cm 2 /electrode area (cm 2 )) with that of Cu-Pt core-shell catalyst, the activity of the latter is still higher. The mass activities of Pt black, Cu-Pt binary alloy, and Cu-Pt core-shell catalysts measured using a rotating disk electrode are 0.053, 0.153 and 0.262 A mg −1 Pt , and their respective specific activities are 197, 496, and 710 μA cm −2 Pt .

Effective Platinum-Copper Catalysts for Methanol Oxidation and Oxygen Reduction in Proton-Exchange Membrane Fuel Cell

“…formed during its electroreduction. At the same time, an excessively strong adsorption interaction can hinder the desorption of reaction products [18,19]. Platinum doping with copper results in a decrease in the interatomic distance of Pt-Pt in the nanoparticles, as well as the change in the energy of free d-orbitals, which facilitates the adsorption of O 2 on the surface of metal nanoparticles [11,[18][19][20].…”

“…To reduce the content of the precious metal in the bimetallic catalyst, while increasing its activity in current-forming reactions, attempts have been made to optimize the composition and structure of platinum-containing nanoparticles [10,13,[18][19][20][21][22][23][24]. Note that the features of the hierarchical structural organization of PtCu/C catalysts are determined not only by the shape and size of the metal nanoparticles, but also by their spatial distribution on the surface of the support, and have a crucial effect on the activity of catalysts in ORR and MOR [20][21][22][23].…”

Catalytic Activities of Pt–Metal Alloys on Oxygen Reduction Reaction in Fluorohydrogenate Ionic Liquid

“…Various potential cathode catalysts such as Pt-M (M = Fe, Co, Ni, etc.) alloy catalysts, [12][13][14][15][16][17][18][19][20][21][22][23] Pt core-shell catalysts, 24,25 and Ptfree catalysts 26,27 have been investigated by many research groups. Among these, Pt alloy catalysts were found to exhibit better ORR activities than Pt in acidic solutions.…”

High Performance Electrocatalysts Based on Pt Nanoarchitecture for Fuel Cell Applications

“…In addition to the development of nanostructured catalysts based on single metal and alloy, many researches have focused on the development of the Pt-based core-shell nanostructures as attractive structures for electrocatalysts in ORR because these structures with designed compositions and morphologies can efficiently reduce the cost of fuel cell manufacturing by significantly reducing the overall amount of Pt required [111][112][113]. Specially, it would be desirable to reduce the amount of Pt at the cathode because the cathode requires 2∼3 times higher Pt loading than required at the anode due to the low kinetic reduction reaction rate in comparison with fuel oxidation reaction.…”