The electrooxidation of acetaldehyde on platinum–ruthenium–rhodium surfaces: A delicate balance between oxidation and carbon–carbon bond breaking

• PtRuRh electrodeposits were used to electrooxidize acetaldehyde in acidic medium.
• The amounts and oxidation charges of acetic acid and CO2 were estimated.
• Ru/Rh ratio plays a pivotal role on the electrooxidation pathways.
• There is a balance between the ability to oxidize adsorbates and break C–C bonds.
• Finely-tuned designed catalysts can improve the oxidation of organic molecules.

In this work we investigate the electrooxidation of acetaldehyde in acidic media on platinum–ruthenium–rhodium electrodeposits of several compositions. Combined results of electrochemistry and in situ FTIR spectroscopy show that the Ru/Rh ratio plays a pivotal role on the electrooxidation of acetaldehyde on PtRuRh surfaces. The combination of these metals apparently establishes a delicate balance between the ability of a surface to oxidize adsorbed species and to promote the C–C bond breaking. Overall, by estimating the charges involved in each oxidation pathway we were able to mimic the electrochemical behavior as a function of the composition. The global output suggests that the proper combination of platinum–ruthenium–rhodium can lead to the development of active catalysts towards the oxidation of small organic molecules.

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