Photothermal Catalytic Conversion of CO2 to CO over Z-Scheme Co9S8@W18O49 Nanotubular Heterostructures

The transformation of CO2 into fuel and valuable chemical products has become an important means to reduce the emissions of greenhouse gases and mitigate the energy crisis. In addition, it is of great significance for achieving the carbon emission peak and carbon neutrality. Herein, Co9S8@W18O49 with a one-dimensional nanotubular core–shell structure was synthesized using a three-step hydrothermal method for photothermal catalytic CO2 reduction. The photocatalytic performance of Co9S8@W18O49 was evaluated by assessing the production of CO under visible light. The results showed that the 25 wt %-Co9S8@W18O49 exhibited an excellent CO production efficiency of approximately 27.4 μmol g–1 h–1, a notable 8.06-fold improvement compared to the pure W18O49 sample. The creation of a heterojunction with a Z-scheme between W18O49 and Co9S8 nanotubes increased the CO2 conversion efficiency and inhibited the recombination of photogenerated charge carriers. Moreover, density functional theory calculations confirmed that the Z-scheme heterojunction was formed. This work aimed to contribute valuable insights into the design of Z-scheme photocatalysts with improved activity, which was enhanced by the synergistic effect of photothermal activation.