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 oxidesupported 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-CeO 2 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 CeO 2 (111) thin films grown on Cu(111) at different temperatures and its effect on Ag growth under ultrahigh vacuum conditions. The strong Zr-CeO 2 interaction leads to a two-dimensional (2D) growth of Zr on the CeO 2 (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 reverse oxygen spillover from ceria substrate to Zr clusters occurs, leading to the formation of reconstructed zirconia and further reduction of ceria. Deposition of Ag onto the Zr pre-deposited CeO 2 (111) surface results in a three-dimensional growth of Ag nanoparticles with a higher particle density and smaller particle size compared to those on the pure CeO 2 (111) surface under same conditions. In addition, an enhanced thermal stability of Ag particles upon annealing was observed on such mixed oxide surface.

Influence of the Preparation Method of Ag-K/CeO2-ZrO2-Al2O3 Catalysts on Their Structure and Activity for the Simultaneous Removal of Soot and NOx

“…The differences in the ratios show that the formation of bulk oxygen vacancies (V o-b ) are influenced by the different preparation techniques in this study, in agreement with previous work [11]. Additionally, the Ag species supported on ceria can lead to oxygen reverse spillover [9,10], creating V o-s , which are filled by the bulk oxygen of ceria via diffusion [11]. Furthermore, a band was observed at 1052-1064 cm −1 for all catalysts, excluding CVI80, which is due to residual carbonate from the precipitation process using Na 2 CO 3 or following the adsorption of CO 2 .…”

“…supported on ceria can lead to oxygen reverse spillover [9,10], creating Vo-s, which are filled by the bulk oxygen of ceria via diffusion [11]. Furthermore, a band was observed at 1052-1064 cm −1 for all catalysts, excluding CVI80, which is due to residual carbonate from the precipitation process using Na2CO3 or following the adsorption of CO2.…”

“…Recently, Ag/CeO 2 catalysts have been shown to be active for soot combustion [8][9][10][11][12][13][14]. Ceria is a widely used support for soot oxidation catalysts, due to its ability to promote oxygen storage as well as its redox behavior [15][16][17][18][19][20][21].…”

On-Surface Pseudo-High-Dilution Synthesis of Macrocycles: Principle and Mechanism

“…The detailed description of the endstation can be found elsewhere. 50 The XPS spectra were collected at an emission angle of 60°with respect to the surface normal.…”

An Unusual Two‐Step Hydrolysis of Nerve Agents by a Nanozyme

“…It has been shown theoretically that the introduction of Zr 4+ ions to CeO 2 not only can increase the oxygen release, but also can enhance the thermal stability of its surface vacancies . Furthermore, the OVs created near the Zr 4+ sites are expected to be less mobile than that of the surface having only cerium ions . The Zr‐incorporated CeO 2 nanomaterials (ZCs) required for this study were prepared by co‐precipitation method by changing the Zr/Ce molar ratio at 1 %, 5 % and 10 % to give 1ZC, 5ZC and 10ZC, respectively.…”