Ce2O3/BiVO4 Embedded in rGO as Photocatalyst for the Degradation of Methyl Orange under Visible Light Irradiation

Damian C Onwudiwe,Opeyemi A Oyewo,Boitumelo M Phadi

doi:10.3390/j4020013

Abstract

A p–n heterojunction semiconductor structure composed of Ce3O4 and BiVO4 has been synthesized and then incorporated into reduced graphene oxide (rGO) by the hydrothermal method. The ternary composites were characterized by X-ray diffraction, transmission electron microscopy (TEM), scanning electron microscopy (SEM), electron diffraction spectroscopy (EDS), and UV–vis spectroscopy. The efficiency of the composites as photocatalysts was determined by studying the oxidative degradation of methyl orange in aqueous solution under visible light irradiation. The effect of parameters such as pH, catalyst loading, and concentration of the dye solution was examined in order to determine their influence on the photocatalytic activity of the composites. The composite incorporated into reduced graphene oxide presented the highest percentage (above 90%) in 2 h time, attributed to the effect of the increased surface area. The process of the enhanced photocatalytic activity has been discussed based on the energy band positions of the nanoparticles within the composite.

Highlights

We report the synthesis of Ce2 O3 /BiVO4 embedded in reduced graphene oxide (rGO) and evaluated the photocatalytic efficiency for the degradation of methyl orange under visible light irradiation
The appearance of both the bismuth vanadate and cerium oxide peaks confirmed the coexistence of the two semiconductor oxides in the same system
The particle size of the photocatalyst rated into GO by the hydrothermal method

Summary

Introduction

Bismuth vanadate (BiVO4 ) is a ternary, non-toxic, n-type semiconductor oxide with a layered structure It has drawn a lot of attention due to its nontoxic nature, low cost, and unique properties such as ionic conductivity, ferro-elasticity, light harvesting capacity, and high stability. These are responsible for its potential application in different areas such as electronic devices, gas sensing, pigment industries, and in the photocatalytic decomposition of organic pollutants [1]. It is currently considered as one of the significant photocatalysts that utilizes visible light because of its narrow band gap of 2.4 eV. It is one of the metal oxides, in which the fast recombination rate of the photo-generated electron-hole pairs still hinders its photocatalytic activity [2]

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Conclusion