Spinel‐Type Mixed Metal Sulfide NiCo2S4 for Efficient Photocatalytic Reduction of CO2 with Visible Light

Mixed metal oxides with a spinel structure have exhibited great opportunities for photocatalytic CO2 reduction; however, the abilities of their sulfide counterparts in this promising area are much less reported. Herein, we demonstrate the synthesis of a ternary metal sulfide, namely NiCo2S4, and its first application to catalyze the CO2 photoreduction reaction under visible light irradiation. The NiCo2S4 material is prepared through a coupled solvothermal‐ion exchange strategy, and is fully checked by diverse characterizations, including X‐ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), X‐ray photoelectron spectroscopy (XPS), energy‐dispersive X‐ray spectroscopy (EDX) and N2 sorption measurements. Under visible light irradiation in a classic tandem photochemical system, this non‐noble‐metal NiCo2S4 catalyst affords a considerable activity and high stability for CO2 deoxygenative reduction, delivering a high CO‐liberating rate of 43.5 μmol mg−1 h−1. The in‐situ PL and transient photocurrent measurements reveal that the spinel catalyst can hamper recombination and accelerate transfer of light‐excited charge carriers, and thus boosting the CO2 reduction reaction. At last, a possible mechanism of the NiCo2S4‐catalyzed CO2 photoreduction reaction is proposed. It is light to do it! Spinel‐type mixed metal sulfide NiCo2S4 is prepared through a coupled solvothermal‐ion exchange method. Under the assistance of a ruthenium photosensitizer, the NiCo2S4 catalyst is demonstrated to be of high‐efficiency for photocatalytic CO2 reduction with visible light, affording a notable CO evolution rate of 43.5 μmol mg−1 h−1. Moreover, the NiCo2S4 catalyst also manifests high stability and reusability for the CO2 reduction reaction in the tandem system.