Enhanced photocatalytic and electrochemical performance of TiO2-Fe2O3 nanocomposite: Its applications in dye decolorization and as supercapacitors

Abstract

this work reveals a green combustion route for the synthesis of tio 2 , fe 2 o 3 and tio 2 -fe 2 o 3 nanocomposites as photocatalysts for decolorization of titan Yellow (tY) and Methyl orange (Mo) dyes at room temperature in aqueous solution concentration of 20 ppm under UV-light irradiation. We observed that the tio 2 -fe 2 o 3 nanocomposite shows superior photocatalytic activity for tY dye compared to pure tio 2 and fe 2 o 3 . Rate constant (k) values of tio 2 , fe 2 o 3 and tio 2 -fe 2 o 3 for tY and Mo are 0.0194, 0.0159, 0.04396 and 0.00931, 0.00772 0.0119 kmin −1 respectively. the surface area and pore volume of tio 2 -fe 2 o 3 nanocomposite were found to be 71.56 m 2 /g and 0.076 cm 3 /g, respectively as revealed by Bet studies. from the Barrett-Joyner-Halenda (BJH) plot, the mean pore diameter of tio 2fe 2 o 3 nanoparticles was found to be 2.43 nm. Further, the TiO 2 -fe 2 o 3 nanocomposite showed good electrochemical behavior as an electrode material for supercapacitors when compared to pure tio 2 and fe 2 o 3 nanoparticles resulted in stable electrochemical performance with nearly 100% coulombic efficiency at a scan rate of 10 mV/s for 1000 cycles. Interestingly, the novelty of this work is that the designed supercapacitors showed stable electrochemical performance even at 1000 th cycle, which might be useful for rechargeable supercapacitor applications. the electrochemical properties of the nanocomposites were compared by the data obtained by cyclic voltammograms, charge-discharge tests and electrochemical impedance spectroscopic studies. these results demonstrated that the tio 2fe 2 o 3 nanocomposite showed stable performance compared to tio 2 and fe 2 o 3 nanoparticles at current density of 5 Ag −1 .Recently electrochemical studies have gained significant attention due to energy and environment related issues. Since the discovery of TiO 2 and its applications as photo-anode for battery, splitting of water, supercapacitor, dye removal etc 1 ., many different metal oxides and electrodes have been explored to enhance the energy conversion efficiency. Amongst a variety of semiconductor metal oxides, hematite (α-Fe 2 O 3 ) was found to be a good anode material for supercapacitor application, which could be attributed to its high solar-to-hydrogen efficiency, encouraging optical band gap (~2 eV), outstanding chemical strength as well as ease of availability in the nature. However, α-Fe 2 O 3 exhibits low experimental performance compared with the theoretical values, which is possibly due to poor conducting and oxygen evolution properties in addition to short whole diffusion length. To overcome these problems, various synthetic methods have been tried in the recent past, to improve the experimental performance of α-Fe 2 O 3 .But, solution-based combustion method is a simple, low cost, energy saving, easy to control the surface morphology and particle size 2 . In addition, the materials prepared in this method are organic solvent free as we used water as solvent 3-5 .

Electrochemical properties of biogenic silver nanoparticles synthesized using Hagenia abyssinica (Brace) JF. Gmel. medicinal plant leaf extract

“…The presence of redox peaks in their cathodic and anodic scan is an indication of significant share of pseudo capacitance in the electrochemical process. The reversibility of the redox reaction is measured by the difference (ΔE a,c ) in the anodic (E pa ) peak potential and cathodic (E pc ) peak potential [35]. The anodic and cathodic peaks are correlated to oxidation potential and reduction potential E pa and E pc respectively.…”

Fabrication of Titanium Dioxide/Carbon Fiber (TiO2/CF) Composites for Removal of Methylene Blue (MB) from Aqueous Solution with Enhanced Photocatalytic Activity

“…Water pollution has become a problem of concern in many countries [1][2][3][4][5]. Many dyes in wastewater contain aromatic compounds, which are chemically stable and harmful to human health [6][7][8].…”

Electrochemical and Photocatalytic Properties of Green Nickel Oxide Nanomaterial Synthesized using Plectranthus Amboinicus Plant Leaf Extract

“…10 reveals the electrochemical impedance spectra of NiO electrode before and after charge-discharge subjected to 1500 cycles. After 1500 cycles of chargedischarge, no drastic change in resistance of the electrode was observed as confirmed by AC impedance graph [44]. Thus g-NONM electrode is believed to exhibit greater stability even after charge-discharge behavior.…”