Localized surface plasma resonance enhanced visible–light–driven CO2 photoreduction in Cu nanoparticles loaded ZnInS solid solutions
Visible–light–driven photocatalysts have shown tremendous prospects in solving energy crisis and environmental problems, thanks to their wide spectral response and high quantum efficiency. Several strategies including the expansion of visible light response, the improvement of solar energy utilization and photocatalytic quantum efficiency via more effective separation of photogenerated carriers, are current focuses of research that direct the design and fabrication of viable photocatalysts. Herein, a series of composite photocatalysts assembled from plasmonic Cu nanoparticles (NPs) and Zn3In2S6 (ZIS) solid solutions were synthesized by means of a simple solvothermal method. In comparison with the pristine ZIS semiconductor, the Cu NPs loaded ZIS solid solutions showed greatly enhanced photocatalytic activity, selectivity and stability towards CO2 reduction under visible irradiation. Of note is the optimized ZIS–Cu2 exhibited enhanced CH4 production rate of ca. 292 μL g–1 h–1 and a selectivity of ca. 71.1%, which was among the highest numbers reported hitherto. The localized surface plasma resonance (LSPR) effect, shown by surface Cu NPs, was believed to play a critical role for the enhanced CO2 photoreduction efficiency. More importantly, the introduction of plasmonic Cu NPs could restrain the recombination of photogenerated electron–hole pairs and promote the migration of photogenerated electrons to better participate in the photocatalytic CO2 reduction in the presence of water vapor. This work thus provides a facile means to design robust and flexible composite photocatalysts for visible–light–driven CO2 photoreduction with high efficiency.