In-situ DRIFT investigation of photocatalytic reduction and oxidation properties of SiO2@α-Fe2O3 core-shell decorated RGO nanocomposite

Abstract

in this work, Sio 2 @α-fe 2 o 3 core-shell decorated RGo nanocomposites were prepared via a simple sol-gel method. The nanocomposites were prepared with different weight percentages (10, 30, and 50 wt %) of the Sio 2 @α-fe 2 o 3 core-shell on RGO, and the effects on the structural and optical properties were identified. The photocatalytic reduction and oxidation properties of the nanocomposites in the gas phase were assessed through the reduction of co 2 and oxidation of ethanol using in-situ diffuse-reflectance infrared fourier transform spectroscopy (DRIFT). The prepared nanocomposite with (30 wt %) of SiO 2 @αfe 2 o 3 showed superior photocatalytic activity for the gas phase reduction of co 2 and oxidation of ethanol. enhancement in the activity was also perceived when the light irradiation was coupled with thermal treatment. the DRift results for the nanocomposites indicate the active chemical conversion kinetics of the redox catalytic effect in the reduction of CO 2 and oxidation of ethanol. further, the evaluation of photoelectrochemical co 2 reduction performance of nanocomposites was acquired by linear sweep voltammetry (LSV), and the results showed a significant improvement in the onset-potential (-0.58 V) for the RGO (30 wt %)-SiO 2 @α-fe 2 o 3 nanocomposite. Photocatalysis is an extensively studied process by many researchers to deal with various applications mostly on energy and environmental problems. In recent years, researchers have been focused on reduction of CO 2 into fuels such as carbon monoxide, hydrocarbons, and alcohol using solar driven photocatalysts 1,2. Under the irradiation of light on the photocatalyst, the electrons in the CB and holes in the VB could be involved simultaneously in the reduction and oxidation reactions, respectively. Thermodynamically, the reduction of CO 2 is an uphill reaction, so the band edge position of CB should be more negative than the reduction potential of CO 2 3,4. Meanwhile, for water oxidation, the VB band edge should be more positive. The efficiency of CO 2 reduction is determined by the various kinetic parameters, which is mainly from binding of CO 2 with the catalyst surface. This process takes place with reaction of CO 2 + 2 e− → CO + 1 / 2 O 2 , which combined with free energy of 257 KJ/mol. Finally, the CO would react with hydrogen to form formate and carbonates. Besides, controlled oxidation of ethanol is very demanding for the application of bioethanol, which is preferred for cost-effective organic synthesis 5,6. Ethanol could be oxidized under light irradiation using photocatalyst materials. Photo-induced electrons and holes from the catalyst could react with O 2 and H 2 O, which generates the reactive oxygen species and.OH, and these species oxidize the adsorbed ethanol. There are many methods which can be used for the reduction of CO 2. Electrochemical 7 , photo-catalytic 8 , and hydrothermal 9,10 methods have all been used, but it is the electrochemical and photocatalytic conversion of CO 2 into fuels such as CO, hydrocarbons, and alcohol whic...

Plasma-Catalysis for Volatile Organic Compounds Decomposition: Complexity of the Reaction Pathways during Acetaldehyde Removal

“…In addition, the growth of other infrared spectral features in this region points out the probable formation of other products such as acetone (1697 cm −1 [41]) or formaldehyde. Indeed, the band at 1242 cm −1 can be assigned to molecularly adsorbed formaldehyde [42,43], which has also been reported to present bands at 2913, 2863, 2759, 1648 and 1413 cm −1 [42,44], supporting the presence of formaldehyde on the silver-based catalyst surface after acetaldehyde adsorption.…”

A Bifunctional 2D Interlayered β‐Cu2V2O7/Zn2V2O6 (CZVO) Heterojunction for Solar‐Driven Nonsacrificial Dye Degradation and Water Oxidation

“…Moreover, the CZVO heterojunction possesses two semicircles (a low-frequency small semicircle and a high-frequency larger semicircle), which can be associated with two-phase material formation, as also observed in the case of Fe 2 O 3 /TiO 2 [62] and SiO 2 /α-Fe 2 O 3 . [63] The bare Fe 2 O 3 in both cases possess a single semicircle; however, another circle arises when it forms a heterojunction.…”

Reticular Materials for Artificial Photoreduction of CO2

“…Notably, DRIFTS also reveals the oxidation state of ethanol intermediates in the oxidation reaction of ethanol to CO 2 catalyzed by V 2 O 5 ‐TiO 2 . [ 60 ] The applicability of in situ DRIFTS is wide‐ranging and suitable for various photocatalytic reactions with different temperatures.…”

“…Another method for oxidation state determination of agents in solution or gaseous medium is in situ DRIFTS. [ 58–60 ] This characterization has been commonly established for monitoring the reduction of CO 2 to methanol or methane. Particularly, Yang and Lin reported the application of DRIFTS studies for investigating the adsorption fashion of CO 2 on the surface of SiO 2 @α‐Fe 2 O 3 core–shell on RGO (RGO = reduced graphene oxide).…”