Enhanced Photocatalytic Activity of Hybrid rGO@TiO2/CN Nanocomposite for Organic Pollutant Degradation under Solar Light Irradiation

Martina Kocijan,Lidija Ćurković,Tina Radošević,Matejka Podlogar

doi:10.3390/catal11091023

Martina Kocijan, Lidija Ćurković + Show 2 more

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https://doi.org/10.3390/catal11091023

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Abstract

The three-component hybrid (rGO/TiO2/CN) nanocomposite was prepared in order to enhance the photocatalytic properties of anatase TiO2 nanoparticles (NPs) under solar-like irradiation. The rGO/TiO2/CN was prepared in a mixture of the reduced graphene oxide (rGO, 8 wt%), anatase TiO2 nanoparticles (NPs), and graphitic carbon nitride (g-C3N4, 16 wt%). It was self-assembled through the one-step hydrothermal method, followed by an annealing process. The photocatalyst was thoroughly characterized by means of X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), transmission electron microscopy (TEM), the Brunauer-Emmett-Teller (BET) nitrogen adsorption/desorption technique and UV-Vis diffuse reflectance spectroscopy (DRS). The photocatalytic activity of the TiO2, TiO2/rGO, TiO2/CN and hybrid rGO/TiO2/CN nanocomposite was studied through the degradation of a rhodamine B (RhB) aqueous solution under solar-like irradiation. The results showed that the highest photocatalytic activity was achieved by the rGO/TiO2/CN mixture, which can be attributed to the synergistic effect of the incorporation of both rGO and g-C3N4 with TiO2. Further, the influence of the pH value of the RhB dye aqueous solution and different water matrix (Milli-Q, tap, and alkaline water) on the photocatalytic efficiency of the rGO/TiO2/CN nanocomposite was examined. In addition, a recycle test was performed for hybrid rGO@TiO2/CN to investigate the effectiveness of the photodegradation of RhB dye in three successive cycles. The conducted results indicate that the pH value of RhB dye aqueous solution and water matrices play an important role in the photocatalytic degradation rate.

Highlights

The presence of micropollutants on a large scale, in virtually every aquatic ecosystem, has become a major problem
The photocatalytic ability of prepared TiO2 nanoparticles, TiO2/reduced graphene oxide (rGO) and TiO2/CN nanocomposites, and rGO@TiO2/CN hybrid material was monitored by the photodegradation of rhodamine B (RhB) dye
In the framework of this work, the photocatalytic activity of prepared TiO2 nanoparticles, TiO2/rGO and TiO2/CN nanocomposites, and the rGO@TiO2/CN hybrid material was monitored by the photodegradation of rhodamine B (RhB) dye

Summary

Introduction

The presence of micropollutants on a large scale, in virtually every aquatic ecosystem, has become a major problem. Pollution reaches the environment by different pathways, most abundantly through wastewater treatment [1,2], where currently employed wastewater treatment plants (WWTP) proved ineffective in the decomposition of harmful complexes. Given the global significance of clean water resources, new processing solutions of wastewater are required. In order to meet today’s requirements and quickly introduce new technologies, solutions must be highly efficient, inexpensive and up-scalable. A seemingly effective approach for this global problem employs advanced oxidation processes (AOPs) in the presence of a catalyst. The term AOP is reserved for a highly effective purification reaction in water, where the production of hydroxyl radicals (HO) directly assists the decomposition of harmful organic micropollutants [3,4]

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