Synthesis and characterization of V2O5-Ga2O3 photocatalysts and their application on the photocatalytic reduction of CO2

The photocatalytic reduction of carbon dioxide (CO 2 ) to produce methanol (CH 3 OH) is a promising strategy for clean energy generation. The catalyst, the aqueous medium, and the UV light are essential parameters for the most relevant pair formation (e − /h + ) and a specific selectivity towards the desired product (methanol). The use of G 2 O 3 and V 2 O 5 in the photocatalytic reduction of CO 2 to obtain methanol has been little studied. However, the combination of these oxides is important to generate synergies and decrease the band energy, enhancing the photocatalytic activity in the reduction of CO 2 . In this work, combined V 2 O 5 -Ga 2 O 3 photocatalysts were obtained and studied in the photocatalytic reduction of CO 2 . The photocatalysts were characterized by spectroscopic and microscopic techniques. The results showed that textural properties, such as surface area and morphology, do not influence photocatalytic activity. However, species identified by XPS such as Ga2p 3/2 and Ga2p 1/2 improved the photocatalytic activity, probably due to the formation of vacancies and the bandgap reduction of the combined oxides, in comparison with the single oxides. The contribution of these factors to the interactions of (e − /h + ) pairs with CO 2 to generate methanol is demonstrated.