Highly Selective Production of Ethanol Over Hierarchical Bi@Bi₂MoO₆ Composite via Bicarbonate-Assisted Photocatalytic CO₂ Reduction

Photocatalytic CO₂ reduction is a sustainable and inexpensive method to solve the energy crisis and the greenhouse effect. However, the major stumbling blocks such as poor product selectivity, low yield of the multi-carbon products, and serious recombination of electron-hole pairs hinder practical application of photocatalysts. Herein, a high-performance Bi@Bi₂MoO₆ photocatalyst, Bi nanoparticles grown on the surface of Bi₂MoO₆ nanosheets with oxygen vacancies, was fabricated via a simple solvothermal approach. Benefiting from the abundant active sites and effective separation of photogenerated carriers of Bi₂MoO₆ nanosheets, and the localized surface plasmon resonance effect of Bi nanoparticles, the Bi@Bi₂MoO₆ sample exhibited great photocatalytic CO₂ reduction activity. Furthermore, adding NaHCO₃ into the system not only significantly increased the C₂H₅OH generation rate but also enhanced the product selectivity. In the photocatalytic measurement (0.17 mol L⁻¹ CO₂-saturated NaHCO₃ solution), the highest formation rates of CO, CH₃OH, and C₂H₅OH were reached at 0.85, 0.59, and 17.93 μmol g⁻¹ h⁻¹ (≈92 % selectivity), respectively.