Recent advances on Z-scheme engineered BiVO4-based semiconductor photocatalysts for CO2 reduction: A review

The designs of two or more absorber materials in a Z-scheme charge transfer configuration have paved the way for efficient CO2 photoreduction to high-value chemicals and fuels using the artificial photosynthesis approach. Under visible light irradiation or natural solar illumination, semiconductors that themselves do not satisfy minimum thermodynamic requirements for CO2 reduction or accompanying oxidation reactions can be used for targeted specific half-reactions. In this context, BiVO4 has been extensively investigated for water oxidation showing promising activity under visible-light illumination but is restricted as a single reduction photocatalyst since its conduction band is not negative enough. This review provides an overview of the basic principles and fundamentals of CO2 photoreduction and highlights the recent advances in the literature using BiVO4-based Z-scheme photocatalysts. We show that using BiVO4 as the oxidation photocatalyst, together with a reduction photocatalyst (Cu2O, CdZnS, ZnIn2S4, CuGaS2, g-C3N4, others) and under the Z-scheme charge transfer, is strategic for increasing visible-light absorption and facilitating charge separations while keeping the high redox potentials of the individual semiconductor components. This approach additionally helps to avoid undesired photocorrosion reactions triggered by trapped charges. Finally, some critical comments are raised for future research directions to improve CO2 capture and photocatalytic conversion to green fuels and chemicals.