RETRACTED: Experimental Study of CO2 Conversion into Methanol by Synthesized Photocatalyst (ZnFe2O4/TiO2) Using Visible Light as an Energy Source

Abstract

Ozone layer depletion is a serious threat due to the extensive release of greenhouse gases. The emission of carbon dioxide (CO2) from fossil fuel combustion is a major reason for global warming. Energy demands and climate change are coupled with each other. CO2is a major gas contributing to global warming; hence, the conversion of CO2 into useful products such as methanol, formic acid, formaldehyde, etc., under visible light is an attractive topic. Challenges associated with the current research include synthesizing a photocatalyst that is driven by visible light with a narrow band gap range between 2.5 and 3.0 eV, the separation of a mixed end product, and the two to three times faster recombination rate of an electron–hole pair compared with separation over yield. The purpose of the current research is to convert CO2 into useful fuel i.e., methanol; the current study focuses on the photocatalytic reduction of CO2into a useful product. This research is based on the profound analysis of published work, which allows the selection of appropriate methods and material for this research. In this study, zinc ferrite (ZnFe2O4) is synthesized via the modified sol–gel method and coupled with titanium dioxide (TiO2). Thereafter, the catalyst is characterized by Fourier transform infrared (FTIR), FE-SEM, UV–Vis, and XRD characterization techniques. UV–Vis illustrates that the synthesized catalyst has a low band gap and utilizes a major portion of visible light irradiation. The XRD pattern was confirmed by the formation of the desired catalyst. FE-SEM illustrated that the size of the catalyst ranges from 50 to 500 nm and BET analysis determined the surface area, which was 2.213 and 6.453 m2/g for ZnFe2O4 and ZnFe2O4/TiO2, respectively. The continuous gas flow photoreactor was used to study the activity of the synthesized catalyst, while titanium dioxide (TiO2) has been coupled with zinc ferrite (ZnFe2O4) under visible light in order to obtain the maximum yield of methanol as a single product and simultaneously avoid the conversion of CO2 into multiple products. The performance of ZnFe2O4/TiO2was mainly assessed through methanol yield with a variable amount of TiO2 over ZnFe2O4 (1:1, 1:2, 2:1, 1:3, and 3:1). The synthesized catalyst recycling ability has been tested up to five cycles. Finally, we concluded that the optimum conditions for maximum yield were found to be a calcination temperature of ZnFe2O4at 900 °C, and optimum yield was at a 1:1 w/w coupling ratio of ZnFe2O4/TiO2. It was observed that due to the enhancement in the electron–hole pair lifetime, the methanol yield at 141.22 μmol/gcat·h over ZnFe2O4/TiO2was found to be 7% higher than the earlier reported data.

Synthesis and identification of structural, optical, electrical, and magnetic properties of novel ZnFe2O4/NiO nanocomposites

“…%. Manzoor et al [48] reported a decrease in band gap after the combination of ZnFe 2 O 4 with TiO 2 with a proper 1:1 ratio. As matter of fact, this ratio leads to an effective narrowing of the bandgap and maximum absorption of the visible light.…”

Enhanced Effect of Metal Sulfide Doping (MgS-TiO2) Nanostructure Catalyst on Photocatalytic Reduction of CO2 to Methanol

“…In this study, the MgS-TiO 2 photocatalyst showed maximum yield of 229.1 µmol/g•h of methanol, which is higher than the other reported catalyst. However, the formation of other products, such as formaldehyde, formic acid, as well as backward reaction, still limit the maximum achievable methanol yield [37].…”

Ternary nanocomposite of ZnFe2O4/α-Fe2O3/ZnO; synthesis via coprecipitation method and physical properties characterization

“…As the most practical application for this class of composite photocatalytic activities such as water pollution degradation [10][11][12][13], CO2 reduction [14], photoelectrochemical (PEC) water splitting and hydrogen production [5,15,16] and PEC oxidation of water [17] have become topics of interest as well as biotechnology and nanomedicine [18][19][20][21][22][23] applications. *Address correspondence to this author at the Department of Physics, Faculty of Shahr-e-Qods branch, Islamic Azad University, P.O.…”