Novel and green synthesis of BiVO4 and GO/BiVO4 photocatalysts for efficient dyes degradation under blue LED illumination

Abstract A straightforward, high-yield route was followed to produce visible light active BiVO4 (BV)-based catalysts through the novel, green approaches: metathesis and metathesis-assisted molten salts. The catalysts prepared at room temperature (BV-RT) and 350 °C for 12 h (BV350/12) exhibited spherical-like and highly crystalline plate-like particles, respectively. A novel BV catalyst was prepared by adding graphite oxide, GO/BV. The synthesis conditions affected crystallite size, crystallinity, optical edge, energy gap, specific area characteristics, and photocatalytic activity. GO/BV achieved 100% rhodamine B (RhB) degradation irradiated (300 min) with low-power blue LEDs. The initial reaction rate (-r0) of RhB using the GO/BV was 4.57, 3.42 and 1.31-fold faster than BV-RT, BV350/12, and BV350/2. Catalyst dosage and RhB initial concentration on the photoactivity of GO/BV were analyzed. Trapping experiments established that holes and hydroxyl radicals are the main oxidative species causing RhB degradation, and the mechanism was postulated based on GO/BV. Reusability tests confirmed GO/BV chemical stability. GO/BV reached 74% photodegradation of methylene blue (MB). The photodegradation of the RhB + MB mixture using GO/BV showed that the coexistence of MB diminished the RhB degradation to 86%.