Precisely tailoring the d-band center of nickel sulfide for boosting overall water splitting

d‐band center engineering is an effective approach to manipulate the electronic structure of an electrocatalyst for boosting water splitting performance. However, it is still challenging to precisely tailor the electronic structure with an optimized d‐band center for efficient hydrogen and oxygen evolution reactions (HER and OER) on one single catalyst simultaneously. Focusing on nickel sulfide (NiS), herein we applied dual-atom modification to precisely regulate the d‐band center of NiS, which dramatically enhances its bifunctional activity with outstanding HER and OER performance. Specifically, the V and Fe co-modified NiS achieves ultra-low overpotentials of 68 and 190 mV to output 10 mA cm in 1 M KOH for HER and OER, respectively. Theoretical calculations reveal that the strong electronic interactions between Ni 3d and V 3d/Fe 3d orbitals effectively tailor the d‐band center of NiS, resulting in optimized HER and OER intermediate adsorption, thus boosting the HER and OER simultaneously.