Abundance of Low-Energy Oxygen Vacancy Pairs Dictates the Catalytic Performance of Cerium-Stabilized Zirconia

Yao Peng; Xia-Lan Si; Cheng Shang; Zhi-Pan Liu

doi:10.1021/jacs.4c01285

Abundance of Low-Energy Oxygen Vacancy Pairs Dictates the Catalytic Performance of Cerium-Stabilized Zirconia

J Am Chem Soc. 2024 Apr 17;146(15):10822-10832. doi: 10.1021/jacs.4c01285. Epub 2024 Apr 9.

Authors

Yao Peng¹, Xia-Lan Si¹, Cheng Shang^{1

2}, Zhi-Pan Liu^{1

3

2}

Affiliations

¹ Collaborative Innovation Center of Chemistry for Energy Materials (iChEM), Shanghai Key Laboratory of Molecular Catalysis and Innovative Materials, Key Laboratory of Computational Physical Science, Department of Chemistry, Fudan University, Shanghai 200433, China.
² Shanghai Qi Zhi Institution, Shanghai 200030, China.
³ Key Laboratory of Synthetic and Self-Assembly Chemistry for Organic Functional Molecules, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, Shanghai 200032, China.

PMID: 38591182
DOI: 10.1021/jacs.4c01285

Abstract

Cerium-stabilized zirconia (Ce_1-xZr_xO_y, CZO) is renowned for its superior oxygen storage capacity (OSC), a key property long believed to be beneficial to catalytic oxidation reactions. However, 50% Ce-containing CZO recorded with the highest OSC has disappointingly poor performance in catalytic oxidation reactions compared to those with higher Ce contents but lower OSC ability. Here, we employ global neural network (G-NN)-based potential energy surface exploration methods to establish the first ternary phase diagram for bulk structures of CZO, which identifies three critical compositions of CZO, namely, 50, 60, and 80% Ce-containing CZO that are thermodynamically stable under typical synthetic conditions. 50% Ce-containing CZO, although having the highest OSC, exhibits the lowest O vacancy (O_v) diffusion rate. By contrast, 60% Ce-containing CZO, despite lower OSC (33.3% OSC compared to that of 50% Ce-containing CZO), reaches the highest O_v diffusion ability and thus offers the highest CO oxidation catalytic performance. The physical origin of the high performance of 60% Ce-containing CZO is the abundance of energetically favorable O_v pairs along the ⟨110⟩ direction, which reduces the energy barrier of O_v diffusion in the bulk and promotes O₂ activation on the surface. Our results clarify the long-standing puzzles on CZO and point out that 60% Ce-containing CZO is the most desirable composition for typical CZO applications.