Highly Enhanced Full Solar Spectrum‐Driven Photocatalytic CO2 Reduction Performance in Cu2–xS/g‐C3N4 Composite: Efficient Charge Transfer and Mechanism Insight

An efficient full solar spectrum ultraviolet–visible–near infrared (UV–vis–NIR) light‐driven Cu 2– x S/g‐C 3 N 4 composite photocatalyst is reported, which is fabricated by a facile solvothermal process for CO 2 photoreduction into CO and CH 4 , as confirmed by product analysis and 13 C isotopic test. The composite exhibits superior full solar‐spectrum‐driven CO 2 photoreduction performance than pure Cu 2– x S and g‐C 3 N 4 , which is attributed to the efficient charge transfer due to the formation of intimate interface contact and SC bond coupling between Cu 2– x S and g‐C 3 N 4 based on experimental analyses and theoretical calculations. In particular, the activities of the best composite for CO 2 photoreduction into CO and CH 4 under NIR light irradiation are about 2.6 times and 6.6 times higher than that of Cu 2– x S, whereas no production is measured over g‐C 3 N 4 . A possible mechanism of photocatalytic CO 2 reduction is given based on in situ Fourier transform infrared (FTIR) analysis. This study paves the way to prepare carbon nitride–based photocatalysts with full‐spectrum‐responsive property for efficient CO 2 photoreduction.