Copper vacancy activated plasmonic Cu3-xSnS4 for highly efficient photocatalytic hydrogen generation:Broad solar absorption,efficient charge separation and decreased HER overpotential

Broad absorption spectra with efficient generation and separation of available charge carriers are indispensable requirements for promising semiconductor-based photocatalysts to achieve the ultimate goal of solar-to-fuel conversion.Here,Cu_(3-x)SnS_(4)(x=0-0.8)with copper vacancies have been prepared and fabricated via solvothermal process.The obtained copper vacancy materials have extended light absorption from ultraviolet to near-infrared-II region for its significant plasmonic effects.Time-resolved photoluminescence shows that the vacancies can simultaneously optimize charge carrier dynamics to boost the generation of long-lived active electrons for photocatalytic reduction.Density functional theory calculations and electrochemical characterizations further revealed that copper vacancies in Cu_(3-x)SnS_(4)tend to enhance hydrogen’s adsorption energy with an obvious decrease in its H_(2)evolution reaction(HER)overpotential.Furthermore,without any loadings,the H_(2)production rate was measured to be 9.5 mmol·h^(-1)·g^(-1).The apparent quantum yield was measured to be 27%for wavelengthλ>380 nm.The solar energy conversion efficiency was measured to be 6.5%under visible-near infrared(vis-NIR)(λ>420 nm).