Interaction of Zr with CeO2(111) Thin Film and Its Influence on Supported Ag Nanoparticles

Abstract

Metal–support interaction plays a crucial role in modulating the activity and selectivity of oxide-supported metal nanoparticles in heterogonous catalysis. Zr-doped ceria is a critical component in automotive three-way catalysts. In order to understand the doping effect and Zr–CeO2 interaction at the atomic level, here we employed X-ray photoelectron spectroscopy (XPS) and scanning tunneling microscopy (STM) to comprehensively investigate the structures, morphologies, and interfacial electronic properties of submonolayer coverage of Zr deposited onto 2 nm thick well-ordered CeO2(111) thin films grown on Cu(111) at different temperatures and its effect on Ag growth under ultrahigh vacuum conditions. The strong Zr–CeO2 interaction leads to a two-dimensional (2D) growth of Zr on the CeO2(111) surface and the formation of a homogeneous Zr–O–Ce mixed oxide layer at room temperature, accompanied by partial reduction of Ce from 4+ to 3+ state. At high temperature, both XPS and STM results indicate that the rever...