The Highly Enhanced Efficiency of the Photocatalytic Reduction of CO2 over Bi2WO6 Nanosheets by NaOH Microregulation

Abstract

The photoreduction of CO2 to other products containing carbon through simulated photosynthesis is a promising area of research. However, given the complexity of the CO2 photocatalytic reduction reaction, it is crucial to adjust the structure of the photocatalysts. The focus of this study was on creating NaOH-modified Bi2WO6 nanosheet photocatalysts via a one-step hydrothermal route and using them to convert CO2 into CO through photocatalytic reduction under the condition of not using an electron sacrifice agent. The results of characterizations and activity data showed that adding an appropriate amount of NaOH significantly improved the photoreduction activity of CO2, as seen in the BWO-2 catalyst. The efficiency of photocatalysts could be improved by tuning the band structure through the addition of an appropriate amount of alkali. This adjustment improves the separation of photogenerated carriers and controls the concentration of oxygen vacancy to reduce recombination. As a result, the photocurrent activity is highly enhanced, leading to better reduction performance compared to unmodified photocatalysts. In experiments, the CO yield of the modified photocatalyst BWO-2 remained above 90 μmol/g after four trials, indicating its effectiveness in reducing CO2. This study offers insights into the regulation of band structure in bismuth-based photocatalysts for efficient CO2 reduction.