Ni Vacancy and the Se/S Ratio Regulate the p‐Band Center of Hollow NiSxSe2‐x/Phase Junction CdS to Achieve High Efficiency and Broad‐Spectrum Photocatalytic Performance

Abstract Rational design of defect engineering and interfacial built‐in electric fields of photocatalysts is imperative for renewable energy conversion. Herein, a multi‐strategy involving the introduction of Ni vacancies, the adjustment of the Se/S ratio, and the construction of dual junctions are employed to simultaneously realize NiS x Se 2‐x /phase junction CdS (HCC) an excellent photocatalytic activity and broad light absorption. With the help of V Ni and the regulation of S/Se, the local electrons are redistributed to occupy more antibonding orbitals and adjust the p‐band center, thus optimizing the H * adsorption energy of the catalyst to accelerate the photocatalytic reaction kinetics. Meanwhile, the synergistic effects of phase junction and heterojunction formations generate dual built‐in electric fields (BIEF), which further amplify the stepwise separation and migration of photogenerated carriers. Notably, V Ni ‐NiSSe/HCC achieves an optimal H 2 evolution rate of 11.43 mmol·g −1 ·h −1 under visible light irradiation with the apparent quantum yield (AQY) at 15.3% at 420 nm, which is 53 times and 26.6 times higher than H‐CdS and HCC, respectively. Additionally, it also exhibits a hydrogen evolution rate of 147 µmol·g −1 ·h −1 under near‐infrared (NIR) light with λ ≥780 nm. This work provides new insight into designing robust photocatalysts by regulating the electronic states and energy states.