ScholarWorks@성균관대학교

초록

Excessive d–p orbital hybridization in nickel-based phosphides fundamentally constrains their electrocatalytic activity for water splitting. Using Ni5P2 as a model system, we present a Mo-triggered electron flow reversal (EFR) strategy to precisely regulate electronic redistribution and orbital hybridization. Density functional theory (DFT) calculations combined with in-situ characterizations demonstrate that the formation of Mo–P–Ni bridging bonds reverses the intrinsic electron transfer pathway, converting the native Ni → P ← Ni configuration in pristine Ni5P2 into a Mo → P → Ni electron flow. This electronic reconfiguration optimizes d–p orbital hybridization, simultaneously balancing hydrogen adsorption–desorption kinetics for hydrogen evolution reaction (HER) and promoting rapid surface reconstruction into catalytically active nickel (oxy)hydroxide species for oxygen evolution reaction (OER). Consequently, Mo-doped Ni5P2 delivers outstanding bifunctional performance under industrially relevant conditions (30 wt% KOH, 60 °C), achieving 10 mA cm–2 at a low cell voltage of 1.457 V. This work establishes electron flow reversal as an effective strategy to manipulate orbital hybridization, offering a rational design principle for advanced electrocatalysts.

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