Electrothermal Oxidation of Ethylene Glycol Over Co ₃ O ₄

Abstract

ABSTRACT Purely electrocatalytic routes for the selective oxidation of alcohols are often limited by overpotential, mass transport, and kinetics due to multiple proton‐coupled electron‐transfer steps. We report the electrothermal oxidation of ethylene glycol (EG) over cobalt oxide (Co 3 O 4 ) spinel acting simultaneously as an electrocatalyst and a solid thermocatalyst by integrating enhanced temperature and 15 bar O 2 pressure in alkaline electrolyte at controlled current density. Enhanced EG oxidation was observed with increasing temperature from 30°C to 90°C. Glycolate and formate were the main products, while oxalate was only detected in long‐term experiments at lower current densities. Selectivity shifted from formate at low temperature, caused by electrochemical C–C cleavage, to rapid glycolate desorption at increased thermal conditions. The virtual Faradaic efficiencies (vFEs), which are the sum of all charge stored in the reaction products, reached 180% at 90°C, confirming that thermal oxidation by O 2 at high pressure contributes to an additional oxidative electron transfer at the solid‐electrolyte interface beyond the applied electrochemical potential. These findings demonstrate that superimposing thermal and electrochemical driving forces boosts performance and enables control over reaction pathways. The approach establishes a conceptual and practical framework toward synergy between electro‐ and thermocatalytic heterogeneous alcohol oxidation toward sustainable chemical transformations.