Accelerating Alkaline Hydrogen Oxidation on Nickel via Engineering the Potential of Zero Charge through...

Nickel is a promising nonprecious electrocatalyst for the alkaline hydrogen oxidation reaction (HOR), yet its activity and stability trade-off remains challenging. Rationally tuning the potential of zero charge (PZC) enables fundamental control over the interfacial electric field and local structural environment under operating potentials, providing a powerful lever to enhance electrocatalyst performance. Here, we introduce the phosphorus (P)-doped carbon shell layer as the surface modifier for Ni-based catalysts to accelerate the HOR kinetics. The resulting Ni@PC catalyst delivers an intrinsic activity of 62.8 μA cm^-2, 1.2 times that of Ni@NC, and retains 94% of its initial activity after stability test, ranking among the most potent Ni-based HOR catalysts reported. Experimental and theoretical analysis reveal that P-doped carbon shell leads to a negative shift in the PZC of the Ni catalyst. The modification alleviates cation crowding of cations, and reconstructs the interfacial hydrogen bonding network, thereby accelerating OH^- transfer. Furthermore, the electronic structure of the Ni core is modulated by a downshift in the d-band center, weakening the H_ad and suppressing the excessive adsorption of OH, which synergistically boosts both activity and stability. This work presents an interfacial engineering strategy to enhance the performance of nonprecious electrocatalysts for hydrogen electrocatalysis.