Efficient photoelectrochemical real textile wastewater detoxification using photoanodes of C3N4-BiVO4

Photoelectrochemical systems utilizing solar energy have garnered significant attention for their sustainability in remediating contaminated water. This study focuses on advancing photoanode development through the utilization of carbon nitrides (C3N4) and bismuth vanadate (BiVO4), two promising semiconductor materials renowned for their efficient electron-hole pair separation leading to enhanced photocatalytic activity. Four distinct materials were synthesized and compared: BiVO4 over C3N4, C3N4 over BiVO4, and pristine BiVO4 and C3N4. Upon electrochemical analysis, the C3N4-BiVO4 heterostructure exhibited the highest photoelectrocatalytic charge transfer constant, mobility, and lifetime of charge carriers. Capitalizing on these exceptional properties, the composite was applied to remove organic matter real effluent from the textile industry. The photoelectrodegradation of the effluent demonstrated substantial removal of Total Organic Carbon (TOC) and the generation of low toxicity degradation products, accompanied by low energy consumption. The compelling results underscore the high potential of the synthesized C3N4-BiVO4 heterostructure for industrial applications, particularly in addressing environmental challenges associated with textile industry effluents.

Effects of Fluorination and Molybdenum Codoping on Monoclinic BiVO4 Photocatalyst by HSE Calculations

Monoclinic phase bismuth vanadate (BiVO₄) is one of the most promising photoelectrochemical materials used in water-splitting photoelectrochemical cells. It could be even better if its band gap and charge transport characteristics were optimized. Although codoping of BiVO₄ has proven to be an effective strategy, its effects are remarkably poorly understood. Using the Heyd-Scuseria-Ernzerhof (HSE) hybrid functional, we estimate the formation energy, electronic properties, and photocatalytic activities of F and Mo codoped BiVO₄. We find that Mo atoms prefer to replace V atoms, whereas F atoms prefer to replace O atoms (F_OMo_V-doped BiVO₄) under oxygen-poor conditions according to calculated formation energies. BiVO₄ doped with F_OMo_V is found to be shallow-level doped, occurring with some continuum states above the conduction band edge, which is advantageous for photochemical catalysis. Moreover, F_OMo_V-doped BiVO₄ shows absorption stronger than that of pure BiVO₄ in the visible spectrum. Based on the band-edge calculation, BiVO₄ doped with F_OMo_V still retains a high oxidizing capacity. It has been shown that F_OMo_V-doped BiVO₄ exhibits a very high photocatalytic activity under visible light.