Fabrication of Ru–CoFe2O4/RGO hierarchical nanostructures for high-performance photoelectrodes to reduce hazards Cr(VI) into Cr(III) coupled with anodic oxidation of phenols. (July 2022)

• Record Type: Journal Article
• Authors: Bharath, G.; Hai, Abdul; Kiruthiga, T.; Rambabu, K.; Sabri, Muhammad Ashraf; Park, Juhyeon; Choi, Myong Yong; Banat, Fawzi; Haija, Mohammad Abu
• Is Part Of: Chemosphere. Volume 299(2022)
• Publication Date: 2022-07
• Subjects: Ferrites -- Photoelectrocatalysts -- Bifunctional photoelectrodes -- Cr(VI) reduction -- Phenol oxidation -- Wastewater treatment; Pollution -- Periodicals; Pollution -- Physiological effect -- Periodicals; Environmental sciences -- Periodicals; Atmospheric chemistry -- Periodicals; 551.511
• DOI: 10.1016/j.chemosphere.2022.134439
• Languages: English
• ISSNs: 0045-6535

Abstract

Abstract: Dual-functional photo (electro)catalysis (PEC) is a key strategy for removing coexisting heavy metals and phenolic compounds from wastewater treatment systems. To design a PEC cell, it is crucial to use chemically stable and cost-effective bifunctional photocatalysts. The present study shows that ruthenium metallic nanoparticles decorated with CoFe2 O4 /RGO (Ru–CoFe2 O4 /RGO) are effective bifunctional photoelectrodes for the reduction of Cr(VI) ions. Ru–CoFe2 O4 /RGO achieves a maximum Cr(VI) reduction rate of 99% at 30 min under visible light irradiation, which is much higher than previously reported catalysts. Moreover, PEC Cr(VI) reduction rate is also tuned by adding varying concentration of phenol. A mechanism for the concurrent removal of Cr(VI) and phenol has been revealed over a bifunctional Ru–CoFe2 O4 /RGO catalyst. A number of key conclusions emerged from this study, demonstrating the dual role of phenol during Cr(VI) reduction by PEC. Anodic oxidation of phenol produces the enormous H + ion, which appears to be a key component of Cr(VI) reduction. Additionally, phenolic molecules serve as hole (h + ) scavengers that reduce e − /h + recombination, thus enhancing the reduction rate of Cr(VI). Therefore, the Ru–CoFe2 O4 /RGO photoelectrode exhibits a promising capability of reducing both heavy metals and phenolic compounds simultaneously in wastewater. Graphical abstract: Image 1 Highlights: Ru–CoFe2 O4 /RGO bifunctional photoelectrode was fabricated for PEC reduction of Cr(VI). A complete reduction of Cr(VI) was obtained at 0.8 V over 30 min under solar illumination. Ru–CoFe2 O4 /RGO were used simultaneously to reduce Cr(VI) and anodic oxidation of phenol. Ru–CoFe2 O4 /RGO photoelectrode has good recyclability and high stability.