Arranging Electronic Localization of PtCu Nanoalloys to Stimulate Improved Oxygen Electroreduction for High-Performance Fuel Cells

Developing exceptionally durable and efficient oxygen reduction reaction (ORR) catalysts is of paramount importance to the widespread commercialization of proton exchange membrane fuel cells (PEMFCs) but is still challenging. Herein, PtCu nanoalloys rooted on nitrogen-doped carbon nanosheets (PtCuNC-700) with fully exposed PtCu nanoalloys and strong metal-support interaction were developed. Benefiting from its structural and compositional merits, PtCuNC-700 showcases superior ORR activity and stability with a specific activity of 1.05 mA cm-2 and mass activity of 0.45 A mgPt-1, 4.2-fold and 3.7-fold higher than Pt/C (0.25 mA cm-2 and 0.12 A mgPt-1), respectively. Moreover, PtCuNC-700 exhibits first-class performance in H2/air PEMFC assessment and delivers a peak power density of 929.7 mW cm-2 and excellent cycling stability up to 30,000 cycles. Theoretical calculations disclose that the synergistic effect of alloying Pt with Cu combined with the strong interaction between PtCu nanoalloys and nitrogen-doped carbon nanosheets can effectively modify the local electron configuration and density of states of Pt sites approaching the Fermi level. Hence, the PtCu-alloy catalysts realized here diminish the energy barrier for ORR and accelerate their reaction kinetics. This work provides a reliable and effective approach to boost the activity and stability of Pt alloy-based ORR electrocatalysts in PEMFCs.