Sulfur adlayer on gold surface for attaining H₂O₂ reduction in alkaline medium: Catalysis, kinetics, and sensing activities

The sensitive detection of hydrogen peroxide (HP) on Au surface is quite challenging owing to the potential dependent decomposition of HP. The current study investigated the development of chemisorbed sulfur adlayer onto the surface of the polycrystalline gold electrode to attain electroreduction of hydrogen peroxide in an alkaline medium using cyclic voltammetry (CV), chronoamperometry, and square wave voltammetry (SWV) measurement techniques. The sulfur adsorbed layer significantly reduces the decomposition of hydrogen peroxide onto the Au (pc) electrode surface allowing the hydrogen peroxide reduction process to proceed. The kinetic diagnosis suggests that the reduction is mass transfer controlled process where electron transfer is the rate determining step in the concerned reduction reaction. The presented electrochemical sensor exhibited high sensitivity and a quick amperometric response to HP in the concentration range of 10-2000 mu M, with a detection limit of 6.0 mu M.