Defect Engineering in CuS x /COF Hybridized Heterostructures: Synergistic Facilitation of the Charge Migration for an Efficacious Photocatalytic Conversion of CO 2 into CO.

The photocatalytic CO 2 reduction reaction (CO 2 RR) 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, Cu 2 S nanospheres and defect-rich Cu 2 S (CuS x ) nanosheets are wrapped by a triazine-containing covalent framework (TP-TA COF), resulting in CuS x /TP-TA and Cu 2 S/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 CuS x /TP-TA proffers a significantly greater photocurrent than Cu 2 S/TP-TA. The subsequent photocatalytic reduction of CO 2 also exhibits an apparently higher CO evolution rate, about 2.8 times higher than the Cu 2 S/TP-TA photocatalyst. The above evident improvement owes much to the heterostructure establishment between CuS x and TP-TA COF, as well as the synergistic effect provided by the defect engineering for CuS x , 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.