Model Building of Metal Oxide Surfaces and Vibronic Coupling Density as a Reactivity Index: Regioselectivity of CO$_2$ Adsorption on Ag-loaded Ga$_2$O$_3$

TL;DR

This study introduces the SSHT model for metal oxide surfaces and demonstrates that vibronic coupling density can serve as a reactivity index, exemplified by analyzing CO2 adsorption regioselectivity on Ag-loaded Ga2O3.

Contribution

The paper presents a novel SSHT model for metal oxide surfaces and establishes VCD as a useful reactivity index for surface reactions.

Findings

VCD effectively predicts surface reactivity.

The SSHT model accurately reflects electronic structures.

CO2 adopts a bent geometry on the catalyst surface.

Abstract

The step-by-step hydrogen-terminated (SSHT) model is proposed as a model for the surfaces of metal oxides. Using this model, it is found that the vibronic coupling density (VCD) can be employed as a reactivity index for surface reactions. As an example, the regioselectivity of CO$_2$ adsorption on the Ag-loaded Ga$_2$O$_3$ photocatalyst surface is investigated based on VCD analysis. The cluster model constructed by the SSHT approach reasonably reflects the electronic structures of the Ga$_2$O$_3$ surface. The geometry of CO$_2$ adsorbed on the Ag-loaded Ga$_2$O$_3$ cluster has a bent structure, which is favorable for its photocatalytic reduction to CO.