摘要
Single-atom catalysts (SACs) featuring precise coordination environments present an effective and low-cost strategy for photoelectrocatalytic (PEC) hydrogen production from water splitting. Herein, 1-5 wt % nickel single atoms (NiSAC) were atomically dispersed onto 2H-phase molybdenum disulfide (NiSAC@2H-MoS2) through a hydrothermal synthesis to serve as the photocathode for H2 production evolved from water splitting. The electron microscopy image and XPS results show that NiSAC, with an average diameter of 0.17 nm, is atomically dispersed onto 2H-MoS2. The Ni K-edge EXAFS analysis corroborates a dominant NiS coordination shell with a bond length of 2.18 Å and a coordination number of 5.78, which provides sufficient active sites to enhance H2 evolution via water splitting. The tailored 2.5 wt % NiSAC@2H-MoS2 exhibits a H2 production rate of 8.78 mmol g−1 h−1 with remarkable stability over 2 h upon applying −0.1 V vs. RHE. The remarkable PEC water splitting is ascribed to the synergistic effect of the intrinsic electric field in 2H-MoS2 and the Schottky barrier at the NiSAC and 2H-MoS2 interface, facilitating efficient charge separation and transfer. Moreover, the NiSAC@2H-MoS2 PEC nanocatalyst exhibits excellent long-term operational stability under continuous solar irradiation, further supporting its practical viability for H2 production. Results of this study highlight the potential of developing the atomically dispersed Ni catalysts as sustainable, noble-metal-free cocatalysts for large-scale solar-to‑hydrogen conversion.
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•Nickel single-atom catalysts anchored on 2H-phase MoS2 was successfully synthesized.•Ni SACs atomically dispersed on the MoS2 surface by NiS coordination with a coordination number of 5.4.•A 2.5 wt% NiSAC@2H-MoS2 exhibits a high HER rate of 8.78 mmol g−1 h−1 with excellent stability.•The internal electric field and Schottky barrier interface enhance charge separation efficiency.