Regulation of Metal−Sulfur bond polarizability in Zn0.5Cd0.5S for visible-light-driven photocatalytic overall water splitting

The development of efficient and stable visible-light-driven Z-scheme systems for overall water splitting was crucial for solar hydrogen production. However, performance was often limited by photocorrosion of sulfide-based hydrogen evolution photocatalysts and competing, deactivating side reactions involving the redox shuttle. Herein, we construct a robust Z-scheme system by employing a CoP-modified Ni-doped Zn 0.5 Cd 0.5 S heterojunction with strong interfacial interaction as the HEP, coupled with BiVO 4 as the oxygen evolution photocatalyst. The optimized system exhibited an apparent quantum yield of 4.06% at 420 nm and enabled sustained co-evolution of hydrogen and oxygen at a near-stoichiometric ratio. It also demonstrated outstanding cycling stability. Crucially, it had been demonstrated that the regulation of the internal polarizability of HEP effectively suppressed the competitive reduction of the redox medium and the formation of passivated Prussian blue derivatives on the catalyst surface. This work provides fundamental insights into mitigating the side effects caused by fusion through polarizability regulation.