Hydrogen adsorption at RuO2(110)

TL;DR

This study uses density functional theory to analyze how hydrogen interacts with the RuO2(110) surface, revealing stable configurations and their implications for catalytic activity.

Contribution

It provides a detailed theoretical analysis of hydrogen adsorption mechanisms and configurations on RuO2(110), enhancing understanding of its catalytic properties.

Findings

Hydrogen stabilizes as molecular and dissociated forms on RuO2(110).

Hydroxyl groups are the most stable low-temperature configuration.

Adsorption increases reactivity of neighboring Ru sites.

Abstract

The structural, vibrational, energetic and electronic properties of hydrogen at the stoichiometric RuO2(110) termination are studied using density functional theory. The oxide surface is found to stabilize both molecular and dissociated H2. The most stable configuration in form of hydroxyl groups (monohydrides) at the undercoordinated O^br surface anions is at low temperatures accessed via a molecular state at the undercoordinated Ru^cus atoms (dihydrogen) and a second precursor in form of a water-like species (dihydride) at the O^br sites. This complex picture of the low-temperature dissociation kinetics of H2 at RuO2(110) is in agreement with existing data from high-resolution energy-loss spectroscopy and temperature programmed desorption. Hydrogen adsorption at O^br sites increases the reactivity of the neighboring Ru^cus sites, which are believed to be the active sites in catalytic oxidation reactions.