Degradation of organic dyes with solar PEC cells based on Bi2S3/BiVO4/TiO2 photoanode

This work focuses on preparing BiVO4/TiO2 and Bi2S3/BiVO4/TiO2 photoanode to degrade organic dyes in water in photoelectrochemical (PEC) cell under irradiation of solar simulator. BiVO4 and Bi2S3 were deposited in porous TiO2 film on FTO glass via in-situ SILAR and anion exchange process in sequence. The phase composition, microstructure and optical properties were analyzed through XRD, TEM and UV–Vis. DRS. The results indicated that Bi2S3 quantum dots (QDs) sensitized further photoanodes to increase the spectral response range and strength, and Bi2S3/BiVO4/TiO2 heterostructure was formed which was beneficial to suppress the recombination of photogenerated carriers. The optimized Bi2S3/BiVO4/TiO2 sample TBS24 achieved the biggest photocurrent density response and the smallest charge interfacial transfer resistance, and the degradation rate of RhB dye was up to 64.3 % within 2.5 h. It is determined that holes and hydroxyl radicals are the key oxidants and degradation mechanism has been discussed systematically.