Tailoring Intermediate Adsorption Through d ‐band Mismatch Strategy of Heterojunction to Achieve Industrial Overall Water Splitting

Adjusting the d-band center of catalysts through heterojunction construction represents an effective approach for enhancing the catalytic activity. Nevertheless, the precise modulation pathways of d-band centers still require systematic elucidation. In this work, a Ni₃Mo/Ni₃N junction is constructed to investigate d-band engineering, and a d-band mismatch mechanism has been proposed for the first time to elucidate the synergistic effect between Ni₃Mo and Ni₃N for improved HER and OER. Specifically, the dissociation of H₂O can be achieved on the Ni₃Mo surface while the adjacent Ni₃N sites catalyze the subsequent evolution reactions. Remarkably, the Ni₃Mo-Ni₃N/NF achieves ultra-low overpotentials of 15 mV (HER) and 155 mV (OER) at 10 mA cm^-2, and just 228 mV (HER) and 459 mV (OER) at 1 A cm^-2. Most strikingly, the HER performance of Ni₃Mo-Ni₃N/NF is superior to that of the Pt/C catalyst across all current densities, marking it as a standout among the NiMo-based catalysts documented so far. Additionally, the Ni₃Mo-Ni₃N/NF demonstrates outstanding performance in an anion exchange membrane water electrolyzer (AEMWE), delivering the current density of 4 A cm^-2 at a mere 2.12 V while maintaining stable operation for 1000 h at 1 A cm^-2, showing great potential for practical applications.