BiVO4 Photoanode Modification by In-Doping and Anoxic Annealing by Synergistic Regulation

In this work, we fabricate a semitransparent BiVO4 photoanode via the synergistic effect of indium (In) doping and anoxic annealing. An optimized photocurrent density of 3.6 mA cm–2 at 2 V versus reversible hydrogen electrode is obtained in a sacrificial free electrolyte system (AM 1.5G 100 mW cm–2). In-doping increases the difficulty to form bonds between Bi atoms and O atoms in the crystal bulk. Thus, quasi-oxygen vacancies in the bulk of the BiVO4 crystal can be induced under anoxic annealing to increase the mobility, lifetime, and concentration of the photogenerated carriers. On the other hand, anoxic annealing can inhibit the conversion rate of the BiOI nanosheet arrays to BiVO4 to form a nanonet structure with a large surface reaction area. Therefore, through a simple In-doping and controlled anoxic annealing process, the photogenerated carriers and the nanomorphology of BiVO4 photoanode are synergistically optimized.