Electrokinetic analysis of water oxidation on alumina supported silver oxide nanopowders
By Butt, Tehmeena Maryum; Ullah, Azmat; Janjua, Naveed Kausar
Published in Journal of Electroanalytical Chemistry
2022
Abstract
This research intended to synthesize γ-Al2O3 supported Ag2O nanopowders (xAg2O/Al2O3, x = 1–5%) in five different compositions for alkaline water electro-oxidation reaction (WEOR). Electrochemical investigations including cyclic voltammetry (CV), linear sweep voltammetry (LSV) and electrochemical impedance spectroscopy (EIS) were performed to examine the electrocatalytic potential of the synthesized nanomaterials. Performed electrochemical (EC) studies designated Ag2O/γ-Al2O3 as a robust electrocatalyst for WEOR. Standard benchmarking protocols were employed to appraise the activity of synthesized catalysts. All catalyst materials exhibited comparable activities by achieving an overpotential of nearly 300 mV at 10 mAcm−2. Results demonstrated that an increase in Ag2O contents reduced the charge transfer resistance (Rct) and augmented EC surface area, ensuing in reduced onset potential (0.98 V vs. Ag/AgCl) and a small Tafel slope (TS) of 0.85 V dec−1. EC analysis revealed high WEOR performance at all Ag2O/γ-Al2O3 modified electrodes, however maximum diffusion coefficient (Do; 6.5 × 10−6 cm2s−1), mass transport coefficient (mt; 7.63 × 10−4 cm s−1), rate constant (ko; 2.4 × 10−4 cm s−1) and low Rct (101 Ω) was observed for 5% Ag2O/γ-Al2O3. This study scheme has proved to be cost-effective synthesis of Ag2O/γ-Al2O3 catalysts providing better fallouts for activity and stability for water oxidation at ambient conditions.