Z-Scheme Heterojunction of SnS(2)/Bi(2)WO(6) for Photoreduction of CO(2) to 100% Alcohol Products by Promoting the Separation of Photogenerated Charges

Using sunlight to convert CO(2) into solar fuel is an ideal solution to both global warming and the energy crisis. The construction of direct Z-scheme heterojunctions is an effective method to overcome the shortcomings of single-component or conventional heterogeneous photocatalysts for photocatalytic CO(2) (carbon dioxide) reduction. In this work, a composite photocatalyst of narrow-gap SnS(2) and stable oxide Bi(2)WO(6) were prepared by a simple hydrothermal method. The combination of Bi(2)WO(6) and SnS(2) narrows the bandgap, thereby broadening the absorption edge and increasing the absorption intensity of visible light. Photoluminescence, transient photocurrent, and electrochemical impedance showed that the coupling of SnS(2) and Bi(2)WO(6) enhanced the efficiency of photogenerated charge separation. The experimental results show that the electron transfer in the Z-scheme heterojunction of SnS(2)/Bi(2)WO(6) enables the CO(2) reduction reactions to take place. The photocatalytic reduction of CO(2) is carried out in pure water phase without electron donor, and the products are only methanol and ethanol. By constructing a Z-scheme heterojunction, the photocatalytic activity of the SnS(2)/Bi(2)WO(6) composite was improved to 3.3 times that of pure SnS(2).