Copper pyrovanadate electrodes prepared by combustion synthesis: evaluation of photoelectroactivity

Abstract

Photoelectrodegradation of dyes using semiconductors under visible light is currently a major research topic. In this work, copper pyrovanadate (Cu2V2O7) was obtained by combustion synthesis, and the influence of different fuels such as citric acid, glycine, and urea on the properties of this semiconductor was evaluated. Using X-ray diffraction analysis, it was observed that the β-Cu2V2O7 phase was formed in greater proportions for the three samples, especially with the use of urea. On the other hand, the formation of the α-Cu2V2O7 phase was not verified when glycine was used, which can be associated with the occurrence of a higher flame temperature during the combustion step (1507 °C). Among the photoelectrodes obtained, the ITO/Cu2V2O7-Urea presented the best photoelectrocatalytic performance, with a greater discoloration rate constant of methylene blue dye (kobs = 28.61 × 10−3 min−1) and less charge transfer resistance (42.75 Ω), while in the other photoelectrodes, the proportion of the β-Cu2V2O7 phase was lower, as well as the discoloration rate constant. Thus, this work has contributed to demonstrate how the choice of fuel can influence the formation of the α- and β-phases of Cu2V2O7 and, therefore, may promote the development of materials with greater stability and photoelectrocatalytic efficiency.