Regulating Exciton Dissociation and Photocatalytic CO2 Reduction Over Single-Atom Cu-In2S3 Nanosheets

Uncovering the excitation processes of photocatalysts and enhancing the dissociation of excitons into free photogenerated electrons and holes for photocatalytic CO 2 reduction is imperative yet quite challenging. Herein, an efficient strategy of reducing the binding energy of excitons to boost exciton dissociation is reported by anchoring the low valence single-atom Cu sites in In 2 S 3 nanosheets (Cu-In 2 S 3 ), which can enhance photocatalytic CO 2 reduction activity. The investigations of photo-irradiated Kelvin probe force microscopy (KPFM), in situ irradiates X-ray photoelectron spectroscopy (XPS), and temperature-dependent photoluminescence (TD-PL) indicate that the doping of low valence single-atom Cu can efficiently drive the charge transfer and separation. Moreover, the studies of the dynamic behaviors of charge carriers by femtosecond time-resolved spectroscopy (fs-TAS) reveal that the doping of low valence Cu single-atom sites allows the promotion of exciton dissociation by reducing the binding energy of the exciton, resulting in an enhanced photocatalytic CO 2 reduction of Cu-In 2 S 3 nanosheets. The aforementioned strategy for enhancing the dissociation efficiency of excitons in photocatalysts will offer a highly efficient and promising approach for the photocatalytic CO 2 reduction and other photocatalytic applications.