First-Principles Study on CO Removing Mechanism on Pt-Decorated Oxygen-Rich Anode Surfaces (Pt₂/o-MO₂(110), M = Ru and Ir) in DMFC

Direct methanol fuel cell (DMFC) is an efficient power source. However, the DMFC anodes are easily toxified by CO or other hydrocarbons, which terminates the methanol oxidation reaction (MOR). The most commonly used high performance catalyst on DMFC anodes is Pt or bimetallic PtRu. In this work, we apply density functional theory (DFT) to investigate the adsorption of CO and H₂O on pristine Pt₂/MO₂(110) and the oxygen-rich Pt₂/o-MO₂(110) surfaces (M = Ru and Ir). We find that the application of the oxygen-rich surfaces significantly reduces the adsorption energies of CO and H₂O molecules as well as the major reaction barrier (CO + OH → CO₂) in the water-gas-shift-like (WGS-like) reactions forming CO₂. Our detailed analyses on the electronic interaction between the catalysts and adsorbates indicate that Pt₂/o-MO₂(110) may be a promising DMFC anode material, which reduces the poison problem, and that it may be the actual experimental system that is responsible for the observed efficient CO removal.