Electrooxidation of Acetaldehyde on Pt(111) Surface Modified by Random Defects and Tin Decoration

摘要

Acetaldehyde oxidation was studied on well-ordered Pt(111), stepped Pt(554), and disordered Pt(111). Random superficial defects of the {110}-type were electro-generated on well-ordered Pt(111) surface by successive potential cycling at 0.05 V s(-1) between 0.05 and 1.3 V in 0.1 M HClO4 solution. In general, well-ordered Pt(111) is more active than stepped or disordered platinum surfaces for acetaldehyde oxidation. The reaction follows a dual pathways mechanism, leading each pathway to CO2 and acetic acid, respectively, as final products. The CO2 is produced via adsorbed CO and CHx reaction intermediates. Acetic acid comes from the adsorbed acetaldehyde oxidation. Additionally, acetaldehyde was also investigated on well-ordered Pt(111) and disordered Pt(111) surfaces, both modified by deposited tin submonolayers. An outstanding performance was observed when both, well-ordered and disordered Pt(111) surfaces, were modified by Sn. It was observed an extraordinary displacement of the onset potential for more negative potentials and an increased production of CO2 and acetic acid.