Regulating glycerol electrooxidation pathways via catalytic environments

Electrocatalytic transformation of abundant organic molecules to value-added chemicals has emerged as a promising pathway towards building a sustainable chemical industry using renewable electricity. As a byproduct of biodiesel production, glycerol can be oxidized electrochemically to synthesize a variety of value-added C1-C3 chemicals including glyceric acid, lactic acid, dihydroxyacetone, glycolic acid and formic acid etc. However, practical glycerol electrooxidation is challenged by limited product selectivity, insufficient activity and poor catalyst stability, which are deeply rooted in the reaction pathway including adsorption, electrochemical dehydrogenation, chemical transformation of intermediates, C-C bond cleavage and product desorption. This review organizes current mechanistic understanding around these coupled steps and examines how catalytic environments, comprising catalyst composition, interfacial properties and reaction conditions, regulate reaction pathways. We elucidate the critical factors that determine the reaction activity and selectivity towards retained C3 or C1/C2 products. Additionally, we distinguish site blocking caused by strongly adsorbed species or slow desorption from deactivation associated with potential-induced surface oxidation and structural evolution. The active-site engineering, regulation of interfacial structure and reaction conditions are connected to the optimisation of electrochemical performance via reactant activation, controlled intermediate transformation, organic residue removal and surface regeneration. This step-resolved perspective provides mechanistic guidance for designing efficient, selective and durable glycerol electrooxidation systems.