Y Doped-Induced Sulfur Vacancy-Mediated Band/Fermi Level Coupling in in₂S₃ for Efficient Pyro-Photoelectrocatalytic...

Pyro-photoelectrocatalytic (Pyro-PEC) water splitting integrates temperature fluctuations with solar irradiation to enable efficient hydrogen production, but conventional In₂S₃ suffers from weak photoresponse, rapid carrier recombination, and poor band alignment, limiting practical applications. To address these limitations, herein we first design and fabricate sulfur vacancy-mediated band bending and fermi level coupling V_S-In_1.90Y_0.10S₃ electrode, for synergistically enhance Pyro-PEC performance. Under Pyro-PEC conditions, the V_S-In_1.90Y_0.10S₃ electrode delivers a high current density of 2.79 mA cm^-2 at 1.23 V vs. RHE, representing a 7.75-fold improvement over In₂S₃, along with significantly enhanced operational stability. Notably, we first employ in situ pyro-photoelectrochemical characterization to unveil that Y doped-induced sulfur vacancies can drastically amplify interfacial band bending and built-in electric field modulation under temperature fluctuations, thereby facilitating directed migration of photogenerated carriers and accelerating interfacial charge transfer. The performance enhancement originates from sulfur vacancy-mediated regulation of local defect states and band structure in In₂S₃, which elevates the Fermi level, optimizes carrier transport and energy distribution, and enables the synergistic reinforcement of Pyro-photoelectrocatalytic field effects under the combined stimuli of temperature fluctuation and photoexcitation. This work establishes a rare-earth doping-enabled defect engineering strategy, providing a novel material design paradigm and mechanistic insight for constructing high-performance Pyro-PEC hydrogen evolution electrodes.