Lattice Defects Coupled with Support Modification Enable a BiNi-Co₃O₄/CP Catalyst for High-Efficiency Acidic Oxygen...

Lattice defect engineering and support modification are effective strategies for modulating catalyst electronic structures and enhancing the intrinsic activity. This study reports the in situ synthesis of a Bi and Ni codoped Co₃O₄ catalyst on carbon paper (BiNi-Co₃O₄/CP) via a one-step molten salt method, integrating dual strategies. Bi doping, with its larger atomic radius, induces abundant lattice defects in the Co₃O₄ surface, optimizing the electronic structure of Co active sites and markedly boosting the inherent catalytic activity. Concurrently, the synergistic interaction between Ni and Bi facilitates the formation of a tailored porous carbon support, which increases the active site exposure and promotes bubble desorption. In situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) confirms that the formation of the *OOH intermediate is significantly lowered by BiNi-Co₃O₄/CP, as is interfacial water adsorption. In 0.5 M H₂SO₄ solution, the BiNi-Co₃O₄/CP catalyst demonstrates outstanding performance for the acidic oxygen evolution reaction (OER), achieving an ultralow overpotential of 275 mV at 10 mA cm^-2 with 110 h stability. This work establishes the synergistic "lattice defect-support modification" approach as a paradigm for designing acidic OER electrocatalysts with high efficiency and stability.