Spin polarization modulated Z-scheme heterostructure for efficient photocatalytic H2 evolution coupled with benzylamine oxidation

Random diffusion of electrons and holes aggravates rapid charge recombination and limits the efficiency of photocatalytic processes. Spin manipulation presents an efficient strategy to regulate charge carrier behavior. Herein, we successfully introduced Cu into sulfur vacancy-rich Mn0.3Cd0.7S (MCS-s), which effectively regulates electron spin polarization and enhances the internal electric field (IEF) within the semiconductor. Through coupling with phosphomolybdic acid hydrate (HPM) to construct Z-scheme heterostructure, we established an efficient pathway for charge carrier migration in the photocatalytic process. DFT calculations and experimental results indicate that sulfur vacancy-induced IEF drives electrons to migrate from the bulk phase to surfacevacancy sites, which accelerates charge carrier transport dynamics for efficient H2 evolution coupled with imine production. Remarkably, the optimized HPM/Cux-MCS-s demonstrated remarkable performance with imine production rates of 15.4 mmol/g/h, along with a high selectivity of 98.0 % towards imine, achieving over 19 times the rate of pristine MCS-s. This work provides new insight into the application of polarized electric field regulation in bifunctional photocatalysts.