Pd/NiSix: An efficient and stable acid-ORR electrocatalyst

An innovative strategy is proposed to enhance palladium (Pd) catalyst activity and stability performance in proton-exchange membrane fuel cells (PEMFCs). By utilizing a corrosion-resistant NiSix alloy as a support for Pd nanoparticles (NPs), the electronic states of active centers are effectively tuned. Pd/NiSix exhibits a significantly increased half-wave potential for the oxygen reduction reaction (ORR) at 0.857 V vs. reversible hydrogen electrode (RHE), with a 3.2-fold mass-specific activity and a 1.7-fold surface-specific activity compared to carbon-supported Pd. Notably, Pd/NiSix demonstrates performance comparable to commercial platinum carbon, including a 12% increase in turnover frequency under PEMFC operating conditions. Density functional theory (DFT) calculations and in situ Raman spectra confirm efficient oxygen adsorption and activation at the NiSix-Pd interface. This approach offers a promising avenue for developing advanced Pd-based electrocatalysts, as an alternative active center, for PEMFCs.