Design and fabrication of ternary BiVO4/FeVO4/Cu2O nanorod array photoelectrode for boosting photoelectrochemical water oxidation

In this study, we demonstrate for the first time the construction of a ternary BiVO 4 /FeVO 4 /Cu 2 O nanorod array (NRA) photoelectrode via seed-assisted refluxing, hydrothermal and successive ionic-layer adsorption and reaction (SILAR) method and its photoelectrochemical (PEC) water oxidation performance. The energy band structures of the BiVO 4 , FeVO 4 and Cu 2 O show that two type-II band alignments with a ladder-like structure are formed in the constructed ternary BiVO 4 /FeVO 4 /Cu 2 O NRA photoelectrode, enabling the photoelectrode to display substantially enhanced PEC performance. The constructed ternary photoelectrode loaded with the optimized Cu 2 O nanoparticles achieves a zero-bias photocurrent density of 50 μA cm −2 , 5 times higher than that of the pure BiVO 4 NRA photoelectrode. The measurements of optical property reveal that the constructed BiVO 4 /FeVO 4 /Cu 2 O nanorod arrays (NRAs) demonstrate improved light absorption capability. The electrochemical impedance and photoluminescence measurements confirm that the charge carriers of the BiVO 4 /FeVO 4 /Cu 2 O heterojunction NRAs are transferred and separated effectively. The substantially boosted PEC water oxidation activity of the constructed ternary BiVO 4 /FeVO 4 /Cu 2 O heterojunction NRA photoelectrode is ascribed to the improved light harvesting and effective charge separation.