Tailoring Zirconia Supported Intermetallic Platinum Alloy via Reactive Metal-Support Interactions for High-Performing Fuel Cells.

Developing efficient and anti-corrosive oxygen reduction reaction (ORR) catalysts is of great importance for the applications of proton exchange membrane fuel cells (PEMFCs). Herein, we report a novel approach to prepare metal oxides supported intermetallic Pt alloy nanoparticles (NPs) via the reactive metal-support interaction (RMSI) as ORR catalysts, using Ni-doped cubic ZrO (Ni/ZrO) supported L1-PtNi NPs as a proof of concept. Benefiting from the Ni migration during RMSI, the oxygen vacancy concentrations in the support are increased, leading to an electron enrichment of Pt. The optimal L1-PtNi-Ni/ZrO-RMSI catalyst achieves remarkably low mass activity (MA) loss (17.8 %) after 400,000 accelerated durability test cycles in a half-cell and exceptional PEMFC performance (MA=0.76 A mg at 0.9 V, peak power density=1.52/0.92 W cm in H-O/-air, and 18.4 % MA decay after 30,000 cycles), representing the best reported Pt-based ORR catalysts without carbon supports. Density functional theory (DFT) calculations reveal that L1-PtNi-Ni/ZrO-RMSI requires a lower energetic barrier for ORR than L1-PtNi-Ni/ZrO (direct loading), which is ascribed to a decreased Bader charge transfer between Pt and *OH, and the improved stability of L1-PtNi-Ni/ZrO-RMSI compared to L1-PtNi-C can be contributed to the increased adhesion energy and Ni vacancy formation energy within the PtNi alloy.