Photoelectrochemical oxidation of glycerol on hematite: thermal effects, in situ FTIR and long-term HPLC product analysis

Photoelectrochemical (PEC) oxidation of biomass is a profitable approach to produce hydrogen by substituting the water oxidation reaction in the electrolyzers’ photoanodes. Among the biomass-derived molecules, glycerol is an interesting alternative to water since its standard thermodynamic potential is considerably lower than that of water and because it is widely produced in the biodiesel industry. Herein, we performed a fundamental study of the PEC oxidation of glycerol on hematite. In situ FTIR experiments and long-term electrolysis followed by HPLC analysis revealed C1, C2 and C3 oxidation products showing the low selectivity of the reaction under these conditions. We explained this lack of selectivity by an electrooxidation mechanism involving highly reactive radicals as intermediates. [Figure not available: see fulltext.].