Defect Engineering in CuSx/COF Hybridized Heterostructures: Synergistic Facilitation of the Charge Migration for an Efficacious Photocatalytic Conversion of CO2 into CO.

Abstract

The photocatalytic CO2 reduction reaction (CO2RR) provides an attractive approach to tackling environmental issues. To actualize the optimal catalytic efficiency, one efficacious strategy is to rationally modulate the charge migration for the adopted heterogeneous catalysts. Herein, by virtue of a one-step hydrothermal method, Cu2S nanospheres and defect-rich Cu2S (CuSx) nanosheets are wrapped by a triazine-containing covalent framework (TP-TA COF), resulting in CuSx/TP-TA and Cu2S/TP-TA. Owing to the heterojunction construction that suppresses the carrier recombination, both hybridized structures present enhanced charge migration in comparison to that of their corresponding sulfides and COF constituents. It is worth emphasizing that CuSx/TP-TA proffers a significantly greater photocurrent than Cu2S/TP-TA. The subsequent photocatalytic reduction of CO2 also exhibits an apparently higher CO evolution rate, about 2.8 times higher than the Cu2S/TP-TA photocatalyst. The above evident improvement owes much to the heterostructure establishment between CuSx and TP-TA COF, as well as the synergistic effect provided by the defect engineering for CuSx, both of which are able to enhance the separation efficiency of photoinduced carriers. Our work sheds light on the rational construction of heterogeneous structures between organic and inorganic photocatalysts, which emphasizes the possible synergistic effect of defect centers for enhancing photocatalytic performance.