Congo Red Dye Degradation by Graphene Nanoplatelets/Doped Bismuth Ferrite Nanoparticle Hybrid Catalysts under Dark and Light Conditions

Abstract

The continuously growing need for clean water has increased research looking for new and efficient ways to treat wastewater. Due to its magnetic properties, Bismuth ferrite, a photo-catalyst, has introduced a novel field of photo-catalysis where the photo-catalytic material could easily be separated from the aqueous solution after wastewater treatment. Herein, a new type of photo-catalysts, composed of Gadolinium (Gd) and Tin (Sn), co-doped Bismuth Ferrite deposited over graphene nanoplatelet surface have been synthesized using a two-step method. In first step, Gd (fixed concentration 10%) and Sn (5%, 15%, 20% and 25%) were doped inside bismuth ferrite (BFO) host using sol-gel method (namely the BGFSO nanoparticles, abbreviated for Gd and Sn doped BFO). In the second step, BGFSO nanoparticles were introduced onto GNPs using co-precipitation method (namely the BGFSO/GNP nanohybrids). The x-ray photoelectron spectroscopy confirmed the chemical bonding between co-doped BFO and GNP sheets via oxy and hydroxyl groups. The photocatalytic activities of the nanohybrids under both, visible light and dark conditions have been increased, and the maximum degradation activity (74%) of organic dye Congo-red (CR) is obtained for 25% Sn-doped BGFSO/GNP nanohybrid. The photocatalytic activity may be attributed to enhanced adsorption capability, electron storage properties of graphene and the presence of oxygen-rich species inside nanohybrids. Based on the current overgrowing population and need for clean water, these materials present versatile potential as catalysts for wastewater treatment.

Photocatalysis and perovskite oxide-based materials: a remedy for a clean and sustainable future

“…Perovskite materials, due to their unique optical properties, also gained importance in the application of photocatalyst during the last decade. 24,25…”

“…The oxygen or different impurities are added as an electron scavenger to increase the recombination time. 25,104,161,162 The photogenerated electron–hole pair then migrates towards the surface of the photocatalyst and induces the reactive ions (such as OH*, O 2− *, etc. ).…”

Role of cooperative factors in the photocatalytic activity of Ba and Mn doped BiFeO3 nanoparticles

“…18 However, the utilisation of BFO is limited due to rapid charge carrier recombination, and the formation of detrimental defect and trap states in the electronic band structure due to oxygen vacancies. Subsequently, different strategies have been developed to improve its photocatalytic efficiency, e.g., by altering the morphology, [19][20][21] synthesizing composites, [22][23][24][25] exploring nanohybrids, 26 and tailoring its properties via doping. 27 A moderate amount of doping into BFO at both Bi-and Fesites affects its ferroelectric, magnetic and optical properties.…”

The Influence of Photocatalytic Reactors Design and Operating Parameters on the Wastewater Organic Pollutants Removal—A Mini-Review

“…Besides the irradiation source, photocatalyst material and the photoreactors structure play an important role on the photocatalytic performance evaluated based on the pollutant removal efficiency. The additional components such as pumps, valves, pipes and the working regime (static or dynamic) contribute to the overall characteristics of the photocatalytic process [19,20]. Keeping high standards in wastewater treatment procedures require finding a suitable balance between the technological parameters, chemical substances consumption and economical costs [21,22].…”