InVO4-BiVO4 composite films with enhanced visible light performance for photodegradation of methylene blue

The InVO4, BiVO4, and InVO4-BiVO4 films were fabricated by a simple doctor blading coating technique. The film thickness of the as-prepared samples was varied to one, two and three layers. The prepared InVO4-BiVO4 composite films were characterized in detail by various analytical techniques that reveal the well crystallinity with orthorhombic structure of InVO4 and monoclinic structure of BiVO4 for the as-prepared material. The as-synthesized photocatalyst films were used as the efficient photocatalysts for the photocatalytic degradation of methylene blue (MB) under visible light illumination. It was found that the three-layered 0.2InVO(4)-0.8BiVO(4) film presented better photocatalytic activity than that of pure phase InVO4 and BiVO4. About 70% of the 1 x 10(-5) g L-1 MB was degraded within 120 min catalyzed by the three-layered 0.2InVO(4)-0.8BiVO(4) films. Interestingly, an obvious synergy between two catalysts was observed and corresponding mechanism based on facilitated transfer of electrons and holes as a result of a suitable energy level alignment was suggested. Fluorescence method with terephthalic acid (TA) as the probe was employed for the quantification of hydroxyl production. (C) 2016 Elsevier B.V. All rights reserved.