In-situ Generation of g-C3N4 on BiVO4 Photoanode for Highly Efficient Photoelectrochemical Water Oxidation

•C3N4/BiVO4 heterojunction photoanodes were fabricated by a simple in-situ method.•Robust and stable photocurrent for PEC water oxidation was achieved.•C3N4/BiVO4 photoanodes were studied by surface photovoltage (SPV) and transient SPV.