Facile one-pot microwave-assisted synthesis of tungsten-doped BiVO₄/WO₃ heterojunctions with enhanced photocatalytic activity

Bismuth vanadate (BiVO₄) is considered one of the most successful candidates to be used as photoanode for solar-to-hydrogen conversion. However, its relatively high recombination rates and considered low long-term stability limits its applicability. Doping BiVO₄ with tungsten and developing heterojunctions with inorganic perovskites has emerged as strategies to overcome these issues. However, the development of these materials requires plenty of time and energy. Here, we reported the development of a new synthetic method to prepare heterojunctions of tungsten-doped bismuth vanadate (using 1, 3 and 5 % in mass of W) and tungsten oxide. The heterojunctions were prepared in a one-pot microwave-assisted method that takes only 24 min. Photocatalytic efficiency was determined through quantification of the amount of hydroxyl radical, generated by the catalysts when they are irradiated with simulated sunlight, and through photoelectrochemical experiments. The heterojunctions showed enhanced photocatalytic activity, which was ascribed to the adequate alignment of the band edges potentials of the semiconductors. Also, the tungsten doping decreases the recombination rates. Both effects increase the photogenerated charges lifetime.