# CO and O2 Interaction with Kinked Pt Surfaces

## TL;DR

This study explores how CO and O2 interact with kinked platinum surfaces, revealing differences in adsorption and reactivity compared to flat surfaces.

## Contribution

The paper provides new insights into CO oxidation on kinked Pt surfaces, highlighting unique adsorption behaviors and reactivity.

## Key findings

- CO preferentially adsorbs at step edges on kinked Pt surfaces, achieving higher coverage than on flat surfaces.
- Kinked Pt surfaces show significantly higher O coverage compared to Pt(111) surfaces.
- The findings suggest kinked surfaces may have higher ignition temperatures and increased reactivity during CO oxidation.

## Abstract

We investigate the chemical interaction of carbon monoxide
(CO)
and oxygen (O2) with kink atoms on steps of platinum crystal
surfaces using a specially designed Pt curved sample. We aim at describing
the fundamental stages of the CO oxidation reaction, i.e., CO-covered/poisoned
stage and O-covered/active stage, at the poorly known kinked Pt facets
by probing CO uptake/saturation and O2 saturation, respectively.
Based on the systematic analysis that the curved surface allows, and
using high-resolution X-ray photoemission, a diversity of terrace
and step/kink species are straightforwardly identified and accurately
quantified, defining a smooth structural and chemical variation across
different crystal planes. In the CO-saturated case, we observe a preferential
adsorption at step edges, where the CO coverage reaches a CO molecule
per step Pt atom, significantly higher than their close-packed analogous
steps with straight terrace termination. For the O-saturated surface,
a significantly higher O coverage is observed in kinked planes compared
to the Pt(111) surface. While the strong adsorption of CO at the kinked
edges points toward a higher ignition temperature of the CO oxidation
at kinks as compared to terraces, the large O coverage at steps may
lead to an increased reactivity of kinked surfaces during the active
stage of the CO oxidation.