Rational Design of Stable and Highly Active Ni Single-Atom Catalysts for Efficient Photocatalytic Hydrogen Production

Single-atom catalysts (SACs) represent a new hotspot and frontier in the field of catalysis, owing to their high atomic utilization and unique electronic structure. However, metal particles at the single-atom level are affected by the Gibbs–Thomson effect, which leads to obvious atomic agglomeration phenomena, resulting in a decrease in photocatalytic hydrogen efficiency. Currently, how to enhance the metal–support interactions to improve the dispersion of metal single atoms is the key to the design of SACs. In addition, the understanding of co-catalyst metal–support interactions is still limited. This understanding is crucial for incorporating metal–support interactions into SACs and maximize their performance via innovative design. In this study, we leverage the modulation of the electronic structure of the catalyst. The optimal Ni SA–Zn _0.67 Cd _0.33 SSe _0.5 catalyst exhibited a photocatalytic hydrogen production performance up to 125.1 mmol g ⁻¹ h ⁻¹ at 10 °C, superior to many previously reported inorganic semiconductor photocatalysts. In particular, the hydrogen production could reach 168.1 mmol g ⁻¹ h ⁻¹ without cooling, due to the photothermal effect. Integrated experimental and theoretical studies reveal that incorporating electronegativity-modified dopants (Se/Te) into Ni SACs effectively tunes the electronic structures of active sites through Ni-S/Zn bond formation. This synergistic modification not only optimizes metal-support interactions via electronic configuration tailoring, but also regulates hydrogen adsorption energy (ΔGH*) and reaction barriers, thereby significantly enhancing the photocatalytic hydrogen evolution reaction (HER) activity. Our study demonstrates a rational design strategy for single-atom catalysts through electronic structure modulation, and investigates photothermal synergistic single-atom catalytic hydrogen production, which is expected to overcome efficiency limitations in solar fuel production.