Cerium-doped indium vanadate microspheres loaded onto the 2D conductive matrix for boosted photodegradation of persistent organic pollutants

Abstract

Photocatalysis has emerged as the most promising protocol for the removal of persistent organic compounds from wastewater, but the shortcomings of photocatalysts, including low absorption in the visible part of the spectrum and fast recombination of separated charge carriers, limits their efficiency, and refute the practical applicability of the method. In the present Investigation, we have synthesized pure and cerium-doped microspheres of indium vanadate and loaded the doped microspheres on the 2D conductive matrix to develop the photocatalyst with high visible light absorption and significant charge separation. The fabricated photocatalysts (InVO₄, Ce:InVO₄, and Ce:InVO₄/rGO) were characterized by various physical, thermal, electrical, electrochemical, and photoelectrochemical techniques. The cerium-doping and loading of microspheres onto the rGO matrix tunes the optical band gap (2.23 eV), increases the conductivity (1.02 × 10⁻² Sm⁻¹), reduces the charge (electron) transfer resistance (22.51 Ω), and enhances the photocurrent intensity of InVO₄. The results manifest substantially improved absorption in the visible part of the spectrum with boosted charge carrier separation. The photocatalytic activity of the designed photocatalyst (Ce:InVO₄/rGO) was estimated by degrading the Rhodamine B dye and ciprofloxacin drug. In 90 min, 95 % degradation of Rhodamine B and 88 % of ciprofloxacin were achieved. The kinetics study revealed the Pseudo-first-order reaction kinetics model for the degradation of both targeted pollutants. Scavenging studies were followed through to get insights into the catalytic active species produced and their relative participation in the degradation of Rhodamine B and ciprofloxacin. The catalyst was cycled to explore the stability for its practical applicability in removing persistent organic compounds.