PtCu₃ nanoalloy@porous PWO_x composites with oxygen container function as efficient ORR electrocatalysts advance the power density of room-temperature hydrogen-air fuel cells

It is challenging and desirable to construct Pt-based nanocomposites with oxygen storage function as efficient oxygen reduction reaction (ORR) catalysts for practical proton exchange membrane fuel cells (PEMFCs). Herein, we achieve novel porous nanocomposites of PtCu₃ nanoalloys-embedded in the PWO_x matrix (PtCu₃@PWO_x), which has an oxygen container feature. The PtCu₃@PWO_x/C exhibits an ultrahigh mass activity (MA) of 3.94 A·mg_Pt⁻¹ for ORR, which is 26.3 times as high as the commercial Pt/C and the highest value ever reported for PtCu-based binary system. Theoretical calculations reveal that the compressive strain and d-band center downshift of Pt intrinsically contribute to the excellent ORR performance. In H₂-air PEMFCs at room temperature, furthermore, the PtCu₃@PWO_x/C delivers a high power density (218.6 mW·cm⁻²), much superior to commercial Pt/C (131.6 mW·cm⁻²). In H₂-O₂ PEMFCs, PtCu₃@PWO_x/C outputs a maximum power density of 420.1 mW·cm⁻². This work provides an effective idea for designing oxygen-storing ORR catalysts used for practical room-temperature H₂-air fuel cells.