Insights into the Effect of Pb on Formic Acid Electro-Oxidation on Pt
Veenu Veenu a, Chinmoy Ranjan a, Dwaipayan Roychowdhury a
a Indian Institute Of Science (Bengaluru Urban, Karnataka), Materials Engineering Department, Banglore, Karnataka, India
Materials for Sustainable Development Conference (MATSUS)
Proceedings of Materials for Sustainable Development Conference (MAT-SUS) (NFM22)
#SusEnergy - Sustainable materials for energy storage and conversion
Barcelona, Spain, 2022 October 24th - 28th
Organizers: Tim-Patrick Fellinger and Magda Titirici
Poster, Veenu Veenu, 164
Publication date: 11th July 2022

Formic acid is a promising energy carrier and electrochemical formic acid oxidation can serve as an important reaction within fuel cells. Although Pt remains the best-known catalyst, but the major current contributing pathways are indirect oxidation pathways, which leads to poor activities at low potentials. The surface adatoms like Pb have been known to promote the direct oxidation pathways significantly. We have carried out theoretical calculations, and experiments to probe the reason for this enhancement. Theoretical results show an upshift of Pt energy levels above the Fermi energy upon adsorption of Pb on the Pt surface, which influences the binding energy of the adsorbates. Reaction free energy calculations of typical intermediates from water (H2O) and formic acid (HCOOH) molecule indicate that Pb adsorption suppresses the adsorption of Hydrogen atoms at potentials typical of underpotential deposition on Pt electrode. This results in a larger number of vacant sites on the Pt surface which is now able to carry out formic acid oxidation to CO2. The calculations were supported by electrochemical experiments of underpotentially deposited hydrogen and potential-dependent apparent activation energies.

The author thanks the Indian Institute of Science start-up research grant, SERC IISc, and the IPC department computing cluster for computing time.

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