Rational synthesis of BixFe1-xVO4 heterostructures impregnated sulfur-doped g-C3N4: A visible-light-driven type-II heterojunction photo (electro)catalyst for efficient photodegradation of roxarsone and photoelectrochemical OER reactions

Metal vanadate (MVO4) and graphitic carbon nitride (g-C3N4) semiconductor materials have attracted much interest due to their tremendous physicochemical and photocatalytic performances. In this prospect, BixFe(1_ x)VO(4) were prepared by mixing cation precursors (Bi and Fe) in different proportions (x = 0.7; 0.5; 0.3) via a simple one-pot hydrothermal route and impregnated on the surface of sulfur-doped g-C3N4(SCN) to attain a wide range of solar absorption and effective charge separation. Several spectroscopic techniques were used to analyze the physicochemical and optoelectronic properties of as-synthesized photocatalysts. The photocatalytic activities of as-synthesized photocatalysts were evaluated by photoelectrochemical oxygen evolution reactions (OER) and photodegradation of roxarsone (ROX). This work aims to investigate the formation, photocatalytic performance, and rational mechanism of BixFe1-xVO4/SCN photocatalytic nanocomposites. Among different BixFe(1_ x)VO(4) (x = 0.7; 0.5; 0.3), the BixFe(1_ x)VO(4)/SCN (Bi/Fe = 0.5) nanocomposite results in 85.66% of ROX photodegradation within 90 mins under visible-light irradiation. The photocatalytic performance of the nanocomposite is about 2.49, 2.87, 3.48 folds higher than that of pristine g-C3N4, BiVO4, and FeVO4 samples, respectively. The photo electrochemical OER results suggest the higher photocurrent density at 1.23 V (vs NHE) was achieved by BixFe(1_ x)VO(4)/SCN (0.987 mA cm(-2)) nanocomposite, and which is 16.73, 5.11, and 6.16 times higher than that of CN (0.059 mA cm(-2)), BiVO4 (0.193 mA cm(-2)), and FeVO4 (0.160 mA cm(-2)), respectively. The XPS and photo electrochemical (PEC) analysis depict the higher donor densities (ND) and excellent charge separations through type-II heterojunction of the BixFe(1_ x)VO(4) nanocomposite.

Automated summary

Metal vanadate and graphitic carbon nitride are semiconductor materials with excellent physicochemical and photocatalytic performances. BixFe1-xVO4/SCN nanocomposites were prepared by mixing cation precursors and impregnating them on the surface of sulfur-doped g-C3N4. The results showed that the nanocomposites exhibited higher photocatalytic activity and photo current density compared to other samples under visible light.