Single-atom copper modified hexagonal tungsten oxide for efficient photocatalytic CO₂ reduction to acetic acid

Selective production of C2+ chemicals from photocatalytic CO2 reduction remains a big challenge due to the inert CO2 molecular and vague C-C coupling process. Herein, contributed by its uniform hexagonal pores, two-dimensional h'-HxWO3 is selected as the support to realize single atom Cu loading (Cu/WO3). Under the irradiation of light, the h'-HxWO3 transformed into electron-and proton-rich tungsten bronze, which ensured the supply and transfer of multiple electrons/protons for the CO2 reduction. Meanwhile, the similar coordination environment and appropriate distance of the Cu active sites presented by the Cu/WO3 not only enable the adsorption and activation of CO2 but also enhance the efficient C-C coupling. Thus, Cu/WO3 photocatalyst achieves the conversion of CO2 to CH3COOH with a selectivity of 67 %, which is about 17 times higher than that of pristine h'-HxWO3. This work expands the route to prepare highly active single-atom catalysts, benefiting CO2 photoreduction to selective reduction products.