Synergistic Ce-ZnIn2S4/ZnS S-scheme heterojunction via a one-step method for efficient CO2 photoreduction

A sulfide–sulfide ZnIn 2 S 4 /ZnS heterojunction establishes an S-scheme charge-transfer pathway with intimate interfacial coupling. • Ce act as additional regulation centers to modulate interfacial electronic structure and carrier dynamics. • The S-scheme charge-transfer mechanism is supported by XPS, KPFM, DFT calculations, and ultrafast spectroscopy. • Ce-mediated electronic regulation synergistically enhances CO 2 adsorption, activation, and surface reduction kinetics. • The optimized C2ZZ2 catalyst achieves 140.6 μmol g −1  h −1 CO production through coordinated interface and electronic regulation. Solar-powered photocatalytic CO 2 reduction represents a promising strategy for achieving carbon neutrality through sustainable solar-to-chemical energy conversion. Nevertheless, inefficient charge separation and sluggish interfacial reaction kinetics markedly limit its performance. Herein, Ce-regulated ZnIn 2 S 4 /ZnS S-scheme heterojunctions were synthesized via a facile one-step in situ hydrothermal strategy to regulate interfacial charge transfer and surface reaction processes. The ZnIn 2 S 4 /ZnS interface establishes an S-scheme charge-migration pathway, facilitating directional migration and utilization of photogenerated carriers, while Ce incorporation induces electronic redistribution and modulates the local electronic environment. Experimental investigations combined with theoretical calculations reveal that Ce-mediated electronic modulation cooperates with the S-scheme heterointerface to strengthen CO 2 adsorption, accelerate interfacial charge transfer, and reduce the energy barrier of CO 2 reduction. Benefiting from this synergistic electronic regulation, the optimized C2ZZ2 catalyst achieves a CO evolution rate of 140.6 μmol g −1  h −1 , approximately 4.5-fold higher than pristine ZnIn 2 S 4 . This work provides mechanistic insights into rare-earth-mediated electronic regulation in metal sulfide photocatalysts, offering a deeper understanding of the relationship among electronic modulation, interfacial charge-transfer dynamics, and CO 2 reduction kinetics. An S-scheme heterojunction, in which ZnS nanospheres are anchored to a defect-containing cerium-doped ZnIn 2 S 4 micro-flowers structure (CxZZy composite), was synthesized via a one-step in situ solvothermal method. This material exhibits outstanding CO 2 catalytic performance under visible light irradiation. Download: Download high-res image (118KB) Download: Download full-size image