Ions-exchange anchoring Cu7S4 cocatalyst on K2Ti8O17 nanowires assembly for enhanced CO2 photoreduction through efficient charge separation

Photocatalytic CO2 reduction into solar fuels has received increasing attention because it is a promising approach to tackle the environment and energy issues we are currently facing. Herein, the composite of K2Ti8O17 nanowires assembly coupled with Cu7S4 cocatalyst has been successfully prepared by an ion exchange method, in which the CuCl is employed as the copper source to convert CdS to Cu7S4. The photocatalytic performance of the integrated K2Ti8O17-Cu7S4 composite is evaluated by CO2 photoreduction, and it exhibits superior photoreduction capability than pristine K2Ti8O17 nanowires assembly. In particular, the K2Ti8O17-Cu7S4-0.2 sample displays the highest CH4 (6.02 μmol g−1 h−1) and CO (0.89 μmol g−1 h−1) yield within 4 h light irradiation, which is 3.83 and 12.71 times higher than that of K2Ti8O17 sample, respectively. Based on the photo/electrochemical test results, the anchoring of Cu7S4 cocatalyst can promote the photogenerated electron-hole pairs separation and charge transfer of the K2Ti8O17, which contributes to more photogenerated electrons participating in the process of photocatalytic CO2 reduction to CH4. This work offers a promising approach to design efficient noble-cocatalyst-free photocatalyst for CO2 photoreduction.