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 mu mol g(-1) h(-1) (approximate to 92 % selectivity), respectively.

Automated summary

Photocatalytic CO2 reduction is a sustainable and inexpensive method to solve the energy crisis and the greenhouse effect. A Bi@Bi2MoO6 photocatalyst with Bi nanoparticles grown on the surface of Bi2MoO6 nanosheets was fabricated, exhibiting great activity due to abundant active sites, effective carrier separation, and localized surface plasmon resonance effect. Addition of NaHCO3 significantly increased C2H5OH generation rate and product selectivity in the system, achieving high formation rates of CO, CH3OH, and C2H5OH in photocatalytic measurement.