Lattice strain engineering of Ni-doped Pd nanoparticles: Realizing efficient and CO-resistant alkaline hydrogen oxidation

The rational design of highly efficient hydrogen oxidation reaction (HOR) catalysts is crucial for the development of new-generation alkaline exchange membrane fuel cell (AEMFC)-based renewable technologies. Lattice strain engineering is proving to be an effective approach for modifying the electronic properties of electrocatalysts. Herein, we introduce ligand assembly pyrolysis techniques aimed at increasing lattice spacing by doping low-valent 3d transition metals, specifically by embedding nickel-doped palladium nanoparticles on hollow mesoporous carbon spheres (Ni-doped Pd/C). Experimental findings indicate that the incorporation of Ni significantly alters the electronic structure and lattice strain of the Pd active sites, enhancing the electronic interaction between Ni and Pd, which in turn improves the adsorption and desorption processes of intermediates. The resulting Ni-doped Pd/C catalyst showcases considerable exchange current density and mass activity of 3.10 mA cm−2 and 2.85 mA μgPd−1, respectively, exceeding those of Pd/C (0.99 mA cm−2 and 0.10 mA μgPd−1) and commercial Pt/C (2.38 mA cm−2 and 0.23 mA μgPt−1). Surprisingly, Ni-doped Pd/C catalyst exhibits strong anti-CO toxic capacity, a feature absenting in commercial Pt/C, suggesting a promising outlook for the broader implementation of AEMFCs in renewable energy technologies.