Synthesis and Characterization of Fe203@y-AI203 N anoparticles for Electrochemical Applications

Abstract

In the present research work, an attempt was made to synthesize electroactive nanocrystalline material for catalyzing oxygen evolution reaction (OER) in alkaline media (1 M KOH). y-alumina was selected as catalytic support and synthesized using the precipitation method with different wt.% compositions of Fe203 loading as active component. The loading was done by means of the impregnation method and 1, 2,3,4,5 , and 10% ofFe203@Ah03 nanocomposites were synthesized. The phase, morphology, and elemental compositions were studied using XRD, FT-IR, SEM, and EDX, while OER studies for all synthesized materials were carried out using different voltametric techniques such as CV; cyclic voltammetry and LSV: linear sweep voltammetry, chronoamperometry and EIS; electrochemical impedance spectroscopy. OER performance of the catalyst in terms of onset potential (Eonset), overpotential (11), current density (1), charge transfer resistance (Ret), and Tafel slopes (b), was calculated. All electrochemical measurements were carried out in three-electrode cell configurations, with subsequent addition of methanol in 1 M KOH electrolyte utilizing catalyst-modified glassy carbon as working electrode while Ag/ AgCl as reference and platinum wire as a counter electrode. Although all the compositions showed good electro catalytic activity for OER, however, AlFe-4 (4% Fe203@Ah03) displayed the best performance with low onset potential (1.61 V), lowest overpotential (0.54 V), and the high current density of74.28 rnA cm 2 at 100 mVs-1 among all the compositions. Highest value of diffusion coefficient (11.4 x 10-8 cm2 S-l) and heterogeneous rate constant (7.0 x 10-4 cm S-l) were also observed for AlFe-4 (4% Fe203@Ah03). This study scheme was proved to be useful for the catalyst synthesis due to minimum use of noble metal active component and replacement with cheaper and effective non noble metal oxide providing better results for activity and stability for water oxidation at ambient conditions.