How decoration with Tl affects CO electro-oxidation on Pd (1 0 0) nanocubes: In situ FTIR and ab-initio insights

Abstract

• Pd nanocubes were synthesized, modified by Tl and tested for CO electrooxidation. • Different amounts of Tl influence CO electrooxidation reaction on these surfaces. • CO adsorbs in a two-site geometry on clean Pd surfaces. • The adsorption geometry changes for on-top in presence of minor amounts of Tl. • DFT data reveals that high Tl coverages hinder CO adsorption on Pd. In this work we prepare Pd (1 0 0) preferentially oriented nanoparticles modified with different amounts of Tl and study the CO electro-oxidation reaction on these surfaces in alkaline medium. The analysis is based on cyclic voltammetry coupled with in situ FTIR spectroscopy, and the results are interpreted with the help of a DFT study. In situ FTIR indicates a change in the CO adsorption geometry on Pd surfaces partially covered by Tl, while DFT data reveal that for high Tl coverages CO adsorption is completely inhibited. Based on our findings, by using the proper amount of Tl, one can think in the development of Pd-based catalysts designed to present tolerance to CO poisoning, aiming their application in the electro-oxidation of small organic molecules.