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 eta(1)(O)-aldehyde and eta(1)(C)-acyl geometry, respectively. The surface atomic arrangement induces different selectivity in the oxidation process.