Copper-antimony sulfide nanostructures with oriented architecture and their efficient CO2 photoreduction

To overcome the limitations of traditional binary sulfide photodegradation and charge recombination, ternary metal sulfide solid solutions provide a promising solution through atomic-level bonding reconfiguration, continuous electron distribution, and the synergy of dual metal sites. In the present study, a Cu 3 SbS 4 solid solution photocatalyst was successfully synthesized via a hydrothermal approach, exhibiting superior performance in the photoreduction of CO 2 , demonstrating high selectivity for the conversion of CO 2 to CO and CH 4 , with yields of 1.8083 mmol g –1 and 0.4232 mmol g –1 , respectively, over a 5-hour reaction duration, alongside excellent cycling stability. Combining in situ spectroscopy with DFT calculations, the enhanced photocatalytic activity of Cu 3 SbS 4 stems from the cooperative bonding effect within its molecular framework. Specifically, the Cu–S bonds form a continuous low-energy barrier path, facilitating electron localization and inhibiting interphase carrier recombination, while the Sb–S bonds construct local active sites on the surface, facilitating CO 2 adsorption and activation. The Electron Localization Function (ELF) analysis indicates that this solid solution overcomes the discontinuous, island-like electron distribution characteristics in the binary system, forming a uniform and continuous network of electron localization, significantly reducing the in situ recombination centers. The synergistic action of the bimetallic (Cu/Sb) sites reduces the key reaction energy barriers, and local lattice distortion exposes high-activity surface sites. Additionally, the elongation of the Cu–S bonds increase the oxidation energy barrier of sulfur, effectively alleviating photodegradation. This study provides atomic-scale evidence for the rational design of bonding cooperation in multi-component sulfide solid solution photocatalysts.