Thermodynamics of the glycerol oxidation reaction: effect of temperature, pH, applied potential, and concentration

Abstract

(Photo)electrochemical glycerol oxidation (GOR) offers a promising route to pair H₂ production with the upgrading of low-value organics into valuable chemicals, yet its implementation is hindered by persistent selectivity challenges. In this work, we present a comprehensive thermodynamic analysis of the full GOR reaction network to clarify how temperature, pH, applied potential, and concentration govern product distribution. We find that temperature and concentration exert only minor influence on selectivity, while pH and applied potential play decisive roles. Elevated pH and high anodic bias substantially increase the thermodynamic accessibility of side reactions, limiting the selective formation of desired products. These results indicate that operating under acidic conditions and avoiding excessive potentials is essential for suppressing competing pathways. Overall, this thermodynamic framework provides clear, actionable guidelines for improving the selectivity and efficiency of GOR systems.