Li Minhan,Zhang Fangzhou,Kuang Min,Ma Yuanyuan,Liao Ting,Sun Ziqi,Luo Wei,Jiang Wan,Yang Jianping
Electrochemical reduction of CO 2 into high-value hydrocarbons and alcohols by using Cu-based catalysts is a promising and attractive technology for CO 2 capture and utilization, resulting from their high catalytic activity and selectivity. The mobility and accessibility of active sites in Cu-based catalysts significantly hinder the development of efficient Cu-based catalysts for CO 2 electrochemical reduction reaction (CO 2 RR). Herein, a facile and effective strategy is developed to engineer accessible and structural stable Cu sites by incorporating single atomic Cu into the nitrogen cavities of the host graphitic carbon nitride (g-C 3 N 4 ) as the active sites for CO 2 -to-CH 4 conversion in CO 2 RR. By regulating the coordination and density of Cu sites in g-C 3 N 4 , an optimal catalyst corresponding to a one Cu atom in one nitrogen cavity reaches the highest CH 4 Faraday efficiency of 49.04% and produces the products with a high CH 4 /C 2 H 4 ratio over 9. This work provides the first experimental study on g-C 3 N 4 -supported single Cu atom catalyst for efficient CH 4 production from CO 2 RR and suggests a principle in designing highly stable and selective high-efficiency Cu-based catalysts for CO 2 RR by engineering Cu active sites in 2D materials with porous crystal structures.
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.
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