Synergistic effect of Pt-Ni dual single-atoms and alloy nanoparticles as a high-efficiency electrocatalyst to minimize Pt utilization at cathode in polymer electrolyte membrane fuel cells

Due to the synergistic affect between Pt, Ni SAs and Pt-Ni alloy NPs, the prepared PtNiSA-NPS-NDC catalyst delivered a superior Pt utilization efficiency. [Display omitted] •Dual single-atoms of Pt, Ni and PtNialloy NPs supported on N-doped carbon was successfully prepared.•The catalyst exhibited impressive ORR catalytic activity in acidic medium.•The catalyst delivered a superior Pt utilization efficiency of 0.033gPt kW−1 as cathode in PEMFC.•The main active sites of the designed catalyst for ORR was determined through DFT calculations. Pt-Ni (111) alloy nanoparticles (NPs) and atomically dispersed Pt have been shown to be the most effective catalysts for oxygen reduction reaction (ORR) in polymer electrolyte membrane fuel cells (PEMFCs) as well as less expensive compared to pure Pt NPs. To meet reaction kinetic demands and minimize the Pt utilization at cathode in PEMFCs, we propose a novel electrocatalyst composed of dual single-atoms (Pt, Ni) and Pt-Ni alloy NPs dispersed on the surface of N-doped carbon (NDC); collectively, PtNiSA-NPS-NDC. The optimized PtNiSA-NPS-NDC catalyst displays excellent mass activity and durability compared to commercial Pt/C. Electrocatalytic measurements show that the PtNiSA-NPS-NDC catalyst, with a metal loading of 4.5 wt%, exhibited distinguished ORR performance (E1/2 = 0.912 V) through a 4-electron (4e-) pathway, which is higher than that of commercial 20 wt% Pt/C (E1/2 = 0.857 V). The DFT simulations indicate Pt-Ni alloy NPs and PtNiN2C4 atomic structure are the mobile active sites for ORR catalytic activity in PtNiSA-NPS-NDC. As a cathode catalyst in PEMFC, the Pt utilization efficiency in the PtNiSA-NPS-NDC catalyst is 0.033 gPt kW−1, which is 5.6 times higher than that of commercial Pt/C (0.185gPt kW−1). Therefore, the consumption of precious metals is effectively minimized.