Methanol assisted water electrooxidation on noble metal free perovskite: RRDE insight into the catalyst's behaviour

Abstract

In this work we have hypothesized that noble metal-free perovskites are an essential class of oxygen evolution reaction (OER) catalysts in an alkaline medium and thus they are a suitable candidate for the assisted water oxidation catalysts. Herein, we demonstrate that the origin of the methanol assisted OER activity at near thermodynamic potential on perovskite electrode arises due to the involvement of additional hydroxyls as a result of dissociative chemisorption of methanol. When the perovskite electrode is screened for methanol electrooxidation reaction in 0.5 M KOH + 0.5 M methanol electrolyte, it delivers a two times higher current density. This imparts an 82% increase in the evolution of oxygen gas moles with complete oxidation of methanol to carbon dioxide. Along with the electrochemical characterization to understand the electrocatalyst property, Rotating ring disk electrode (RRDE) technique is explored for the first time in literature to validate the catalyst's involvement during OER. RRDE is found effective to understand the lattice oxygen behaviour and methanol assisted electrooxidation of water during OER. Our results suggest new insights and ideas towards oxygen evolution reaction process and the mechanistic insight into the elevated OER due to assisted methanol electrooxidation.