Human beings are dependent on the environment for stable survival and sustainable development. However, human being-environment interaction is causing many environmental devastations which caused excessive negative impacts on the inhabitants. Industrialization is among the human activity where illegal waste disposal is mostly practiced. The waste disposed to the environment comprises many toxic pollutants including carcinogenic and mutagenic heavy metals. Hexavalent chromium is among the heaviest metal contaminants which cause serious health problems to living organisms. Hence, photocatalysis is the promising green technology to detoxify it. For this purpose, bimetallic (In,Ga)2(O,S)3 oxy-sulfide nanoflower catalyst with different Ga contents was successfully synthesized at a low temperature of 150 oC via a facile method. The oxy-sulfide catalysts were systematically characterized and the catalyst with InCl2-4H2O:Ga(NO3)3-8H2O at 1:0.50, designated as SA-2, revealed 100% Cr(VI) reduction at 4 min under visible light irradiation. The Cr(VI) reduction reaction rate constant was 13.8 fold higher than that of Ga-free In2(O,S)3 catalyst. The photoexcited electrons and H+ ions played crucial roles in the reduction of Cr(VI). The photocatalytic activity of the bimetallic oxy-sulfide nanoflower catalyst was further enhanced via composite formation with V2O5. The oxy-sulfide based V2O5@(In,Ga)2(O,S)3 nanocomposite catalyst, at different weight percentages of V2O5, was successfully synthesized via a simplistic procedural route. The two pure catalysts were intimately allied and used for enhanced visible light-assisted reduction of Cr(VI). The nanocomposite catalysts were characterized to observe the effects of V2O5 on crystal phase, morphology, light absorption, catalytic activity, and electrical properties. Compared to all, 40% V2O5 loaded nanocomposite catalyst, designated as VOS-2, exhibited the best-reducing capability. It completely reduced toxic Cr(VI) in 2 min under visible light irradiation, where its rate constant was increased by a factor of 3.6 compared to the pure (In,Ga)2(O,S)3 nanoflower catalyst. The plausible mechanism of charge transfer process across the interfacial region indicates the diminished recombination probability of photogenerated charge carriers. Therefore, the single phase (In,Ga)2(O,S)3 nanoflower catalyst and V2O5@(In,Ga)2(O,S)3 nanocomposite catalyst are promising for enhanced reduction of Cr(VI) in the Cr-based industrial activities, which is significantly relevant for environmental remediation.

Human beings are dependent on the environment for stable survival and sustainable development. However, human being-environment interaction is causing many environmental devastations which caused excessive negative impacts on the inhabitants. Industrialization is among the human activity where illegal waste disposal is mostly practiced. The waste disposed to the environment comprises many toxic pollutants including carcinogenic and mutagenic heavy metals. Hexavalent chromium is among the heaviest metal contaminants which cause serious health problems to living organisms. Hence, photocatalysis is the promising green technology to detoxify it. For this purpose, bimetallic (In,Ga)2(O,S)3 oxy-sulfide nanoflower catalyst with different Ga contents was successfully synthesized at a low temperature of 150 oC via a facile method. The oxy-sulfide catalysts were systematically characterized and the catalyst with InCl2-4H2O:Ga(NO3)3-8H2O at 1:0.50, designated as SA-2, revealed 100% Cr(VI) reduction at 4 min under visible light irradiation. The Cr(VI) reduction reaction rate constant was 13.8 fold higher than that of Ga-free In2(O,S)3 catalyst. The photoexcited electrons and H+ ions played crucial roles in the reduction of Cr(VI). The photocatalytic activity of the bimetallic oxy-sulfide nanoflower catalyst was further enhanced via composite formation with V2O5. The oxy-sulfide based V2O5@(In,Ga)2(O,S)3 nanocomposite catalyst, at different weight percentages of V2O5, was successfully synthesized via a simplistic procedural route. The two pure catalysts were intimately allied and used for enhanced visible light-assisted reduction of Cr(VI). The nanocomposite catalysts were characterized to observe the effects of V2O5 on crystal phase, morphology, light absorption, catalytic activity, and electrical properties. Compared to all, 40% V2O5 loaded nanocomposite catalyst, designated as VOS-2, exhibited the best-reducing capability. It completely reduced toxic Cr(VI) in 2 min under visible light irradiation, where its rate constant was increased by a factor of 3.6 compared to the pure (In,Ga)2(O,S)3 nanoflower catalyst. The plausible mechanism of charge transfer process across the interfacial region indicates the diminished recombination probability of photogenerated charge carriers. Therefore, the single phase (In,Ga)2(O,S)3 nanoflower catalyst and V2O5@(In,Ga)2(O,S)3 nanocomposite catalyst are promising for enhanced reduction of Cr(VI) in the Cr-based industrial activities, which is significantly relevant for environmental remediation.

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