Electrocatalytic investigation of H2O2 reduction and sensing performance using sulfide modified Au/Pt electrode in alkaline medium

Abstract

Hydrogen peroxide (HP) is extensively utilized in numerous industries for synthesizing various chemicals and as a fueling vector in direct peroxide fuel cells in place of oxygen molecules. Therefore, it is crucial to detect HP quickly and develop a cost-effective method for this purpose. The Au/Pt electrode surface exhibits no substantial electrocatalytic activity towards HP reduction reaction, although facilitates oxygen reduction reaction (ORR). To address this issue, in this work, S2- ions have been partially immobilized on Au/Pt surface (termed as [sub-S-Au/Pt]). This modified electrode eliminated catalytic sites for oxygen reduction and generated catalytic sites for facilitating the HP reduction reaction. Comprehensive electrochemical investigations and characterizations of the developed sensor were carried out using cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), open circuit potential (OCP), chronoamperometry, and Differential pulse voltammetry (DPV) techniques. The relationship between the current response and HP concentration exhibited a wide linear dynamic range (LDR) ranging from 2 to 1500 μM, with a limit of detection (LOD) of 2.3 μM. The sensitivity of the sensor was determined to be 423.7 μA mM−1cm−2. Additionally, this article provides insight into the kinetics of the HP reduction reaction using the [sub S-Au/Pt] electrode in an alkaline medium. The modified electrode surface was characterized using scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS).