Cu-modulated PtCr Intermetallic Nanoparticles: Balancing Activity and Durability for Efficient Oxygen Reduction Reaction

Abstract

We demonstrate a strategy of incorporating Cu into an intrinsically stable PtCr intermetallic compound to construct a small-sized PtCrCu ternary intermetallic electrocatalyst, which exhibits high activity and durability toward the oxygen reduction reaction.Proton exchange membrane fuel cells are regarded as a promising energy conversion technology owing to their high energy conversion efficiency, environmental benignity, high specific energy, and capability for sustainable power output. [1][2][3][4][5][6] However, their large-scale commercialization is still hindered by high cost, limited durability, and sluggish cathodic oxygen reduction reaction (ORR) kinetics. [7][8][9][10][11][12] Therefore, the development of ORR electrocatalysts that simultaneously exhibit high activity and long-term durability remains a critical challenge. Alloying Pt with transition metals has been extensively explored to enhance ORR performance by modulating the electronic structure of Pt and optimizing the adsorption behaviour of oxygen-containing intermediates and reduce costs. [13][14][15][16][17][18] Among various Pt-based alloy catalysts, ordered intermetallic compounds have attracted increasing attention due to their well-defined stoichiometry and highly ordered atomic arrangements, which strengthen metal-metal interactions and effectively suppress the dissolution of non-noble metals under acidic operating conditions. [19][20][21][22][23][24][25][26] In addition, the coordination and lattice strain effects inherent to intermetallic structures further contribute to improved ORR activity. Notably, PtM (M = Fe, Co, Ni, etc.) alloys exhibit exceptionally high ORR activity but suffer from insufficient durability , [27][28][29][30][31][32][33][34][35][36] In contrast, PtCr alloys possess superior intrinsic durability , which has been attributed to the strong Pt-Cr coordination interaction, the corrosion resistance of Cr species, and the relatively small lattice strain within the PtCr intermetallic lattice. However, the strong Pt-Cr