Selective site doping impact on the phase transition in bismuth vanadate

Doping in bismuth vanadate (BiVO4) is widely used to enhance the efficiency of photoelectrochemical water splitting, but the fundamental mechanism is not fully understood due to its correlation with structure distortion and phase transition. Here, we investigate the selective site doping effect on the phase transition behavior of BiVO4 using in-situ high-temperature X-ray diffraction. BiVO4 powders with A-site doping by Gd3+ and B-site doing by Mo6+ are prepared, and transition from monoclinic to tetragonal in these powders is observed in real time with increasing temperature from 30 degrees C to 450 degrees C. Both dopants are found to assist the tetragonal structure distortion and lower the transition temperature. The lowest transition temperature of 210 degrees C is observed in Modoped BiVO4, followed by 220 degrees C in Gd-doped BiVO4 and 235 degrees C in pristine BiVO4. This study delivers mechanistic insights into the doping impact on the structural transition in BiVO4 for efficient photoelectrode design.