Electrooxidation of glycerol on platinum nanoparticles: Deciphering how the position of each carbon affects the oxidation pathways

Highlights: • Glycerol forms CO and CO₂ from both terminal (-¹³CH₂OH) and central (-¹²CHOH-) groups. • The oxidation of the terminal group is easier than that of the central group. • The formation of ¹³CO₂ seems to be favored through a L-H mechanism. • Glyceraldehyde seems to intermediate the formation of glyceric acid. - Abstract: In this work we investigate the electrooxidation of glycerol on platinum nanoparticles in acidic media. By using in situ FTIR and isotopically labeled glycerol (¹³CH₂OH-¹²CHOH-¹³CH₂OH) we follow the reaction during a full cycle of oxidation and unravel the role of some important species on the electrooxidation pathways. Results indicate that terminal (-¹³CH₂OH) and central (-¹²CHOH-) groups are able to form adsorbed CO and that both contribute to the production of CO₂, although the terminal groups are easier to be oxidized than the central one, probably due to the steric effect provoked by -¹³CH₂OH which prevents the oxidation of -¹²CHOH-. Moreover, glyceraldehyde seems to be an important intermediate for the generation of glyceric acid