Electrocatalytic Oxidation of Glycerol on Platinum Single Crystals in Alkaline Media

Glycerol adsorption and oxidation reactivity at platinum single crystal electrodes in alkaline media using electrochemical and Fourier transform infrared (FTIR) techniques are reported. The behavior of Pt(100) and Pt(110) for the glycerol electrooxidation reaction (GEOR) were compared and analyzed altogether with those previously reported for Pt(111) ( R. M. L. M. Sandrini, J. R. Sempionatto, E. Herrero, J. M. Feliu, J. Souza‐Garcia, C. A. Angelucci, Electrochem. commun. 2018, 86, 149–152). The voltammetric profiles confirm the structure sensitivity of GEOR as well as the role of the surface atoms orientation on the electrocatalytic activity. The Pt(100) surface has shown to be less prone to poisoning during multiple potential cycles in contrast to Pt(110), which suffers an accentuate deactivation at the first positive‐going scan. Spectroscopic results show that the GEOR on all three surfaces is characterized by the presence of two broad bands, centered at circa 1400 cm−1 and 1600 cm−1. This provides evidence that the GEOR mechanism undergoes glycerol dehydrogenation to alkoxydes followed by the formation of aldehyde intermediates adsorbed as η1(O)‐aldehyde and η1(C)‐acyl geometry, respectively. The surface atomic arrangement induces different selectivity in the oxidation process. Glycerol electrooxidation on Pt single crystal electrodes is a strongly structure sensitive reaction. In alkaline media the electrode activity is highly suppressed with subsequent potentiodynamic cycles. The Pt(100) electrode is less prone to poisoning in than Pt(110) and Pt(111). In‐situ FTIR results are suggesting that the mechanism undergoes through glycerol dehydrogenation to alkoxydes, followed by formation of aldehyde intermediates adsorbed as η1(O)‐aldehyde and η1(C)‐acyl geometry.