High CO tolerance of Pt/Ru nano-catalyst: insight from first principles calculation

TL;DR

This study uses first principles calculations to explain how Pt/Ru nano-catalysts tolerate CO poisoning, revealing that CO spillover from Pt to Ru reduces poisoning effects and enhances catalyst stability.

Contribution

It provides a detailed electronic structure explanation for CO spillover mechanism in Pt/Ru catalysts based on DFT calculations.

Findings

CO has lowest adsorption at the center of Pt islets

Activation barriers for CO diffusion are below 0.3 eV

CO spillover to Ru substrate explains CO tolerance

Abstract

Density functional theory based calculations of the energetics of adsorption and diffusion of CO on Pt islets and on the Ru(0001) substrate show that CO has the lowest adsorption energy at the center of the islet, and its bonding increases as it moves to the edge of the island and further onto the substrate. Activation energy barriers for CO diffusion from the islet to the Ru surface are found to be lower than 0.3 eV making the process feasible and leading to the conclusion that this hydrogen oxidation catalyst is CO tolerant because of the spillover of CO from active Pt sites to the Ru substrate. We present the rationale for this effect using insights from detailed electronic structure calculations.