Synthesis and Characterization of CuV2O6 and Cu2V2O7: Two Photoanode Candidates for Photoelectrochemical Water Oxidation

Thin films of two copper-based metal vanadates (CuV2O6 and Cu2V2O7) were synthesized by a facile drop-casting method. The primary photoelectrochemical (PEC) and physical properties of these two materials including photocurrent response, band gap, flat band potential, incident photon to current conversion efficiency, chemical stability, and oxygen evolution faradaic efficiency were researched. The photocurrent density of CuV2O6 and Cu2V2O7 films at 1.23 V vs RHE in 0.1 M sodium borate buffer solution was about 25 and 35 μA/cm2, respectively. At 1.58 V vs RHE, however, the photocurrent density reached approximately 220 and 120 μA/cm2, respectively. Although the photocurrents observed for these two materials at 1.23 V vs RHE were relatively low, the photocurrents were much higher when tested with sodium sulfite as a hole scavenger. Suitable oxygen evolution catalysts are therefore expected to improve the PEC performance of these materials.