Imran Hasan

The present work deals with precipitation followed by the hydrothermal method for the synthesis of cerium vanadate decorated nitrogen doped reduced graphene oxide (CeV/NRGO) nanocomposite. The crystallographic and Raman spectroscopic characterization confirm the formation of CeV/NRGO nanocomposite. A computational study on crystal structure using Material Studio, confirms the presence of zircon‐like CeV with VO 4 tetrahedra sharing corners and edges with CeO 8 dodecahedra in CeV/NRGO nanocomposite. X‐ray photoelectron spectroscopic (XPS) analysis supports the presence of Ce in +3 and +4 oxidation state. The optical characterization shows the decreased bandgap in CeV/NRGO nanocomposite (2.03 eV) compared to pristine CeV (2.35 eV). Enhanced photocatalytic activity is observed towards hydrogen evolution in CeV/NRGO (15 124 μmol) compared to CeV (7215 μmol) and NRGO (2034 μmol). In addition, CeV/NRGO, CeV, and NRGO are evaluated for degradation of Alizarin Yellow (AY) and Orange G (OG) dyes in presence of visible light. CeV/NRGO managed to degrade 97% and 94% of AY and OG, respectively in 80 min. The electron spin resonance (ESR) studies show superoxide radicals and hydroxyl ions are the active species responsible for photocatalytic reactions. Based on the liquid chromatography–mass spectroscopy (LC–MS) results, a possible photocatalytic mechanism has been discussed. The good stability and reusability of CeV/NRGO nanocomposite could be a choice of material for energy and environmental related research.

In this study, we utilized calcination and simple impregnation methods to successfully fabricate bare g-C3N4 (GCN) and x% Ag/g-C3N4 (x% AgGCN) composite photocatalysts with various weight percentages (x = 1, 3, 5, and 7 wt.%). The synthesized bare and composite photocatalysts were analyzed to illustrate their phase formation, functional group, morphology, and optical properties utilizing XRD, FT-IR, UV-Vis DRS, PL, FE-SEM, and the EDS. The photodegradation rate of MO under solar light irradiation was measured, and the 5% AgGCN composite photocatalyst showed higher photocatalytic activity (99%), which is very high compared to other bare and composite photocatalysts. The MO dye degradation rate constant with the 5% AgGCN photocatalyst exhibits 14.83 times better photocatalytic activity compared to the bare GCN catalyst. This photocatalyst showed good efficiency in the degradation of MO dye and demonstrated cycling stability even in the 5th successive photocatalytic reaction cycle. The higher photocatalytic activity of the 5% AgGCN composite catalyst for the degradation of MO dye is due to the interaction of Ag with GCN and the localized surface plasmon resonance (SPR) effect of Ag. The scavenger study results indicate that O2●− radicals play a major role in MO dye degradation. A possible charge-transfer mechanism is proposed to explain the solar-light-driven photocatalyst of GCN.