Riboflavin-Immobilized CeO2–RGO Nanohybrid as a Potential Photoredox Catalyst for Enhanced Removal of Organic Pollutants under Visible Light

Abstract

We report a facile immobilization of riboflavin (RF) over in situ synthesized CeO2–reduced graphene oxide (RGO) nanohybrid surface synthesized through a simple wet-chemical approach for photocatalytic degradation of organic pollutants under visible light (λ ≥ 420 nm). The hybrid containing 3% w/w RGO shows an excellent photocatalytic activity under visible light. The UV–visible diffuse reflectance spectra, photoluminescence (PL) analysis, and transient photocurrent measurements corroborate that the hybrid RF@CeO2–RGO significantly absorbs visible light and exhibits lower recombination of charge carriers in comparison to RF@CeO2. The catalyst, RF@CeO2–RGO, offers enhancement in photocatalytic rate, i.e., 2.8-fold increase for methyl orange (MO) and 3.5-fold for p-nitrotoluene (PNT) in comparison to RF@CeO2 under visible light (2 h). This enhancement could be attributed to the synergistic effect among CeO2, RF (broadens visible light absorption region), and RGO (an electron-shuttling agent), which lead to a...