An efficient full solar spectrum ultraviolet–visible–near infrared (UV–vis–NIR) light‐driven Cu2–xS/g‐C3N4 composite photocatalyst is reported, which is fabricated by a facile solvothermal process for CO2 photoreduction into CO and CH4, as confirmed by product analysis and 13C isotopic test. The composite exhibits superior full solar‐spectrum‐driven CO2 photoreduction performance than pure Cu2–xS and g‐C3N4, which is attributed to the efficient charge transfer due to the formation of intimate interface contact and SC bond coupling between Cu2–xS and g‐C3N4 based on experimental analyses and theoretical calculations. In particular, the activities of the best composite for CO2 photoreduction into CO and CH4 under NIR light irradiation are about 2.6 times and 6.6 times higher than that of Cu2–xS, whereas no production is measured over g‐C3N4. A possible mechanism of photocatalytic CO2 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 CO2 photoreduction.
