CuCeOx/CuO Catalyst Derived from the Layered Double Hydroxide Precursor: Catalytic Performance in NO Reduction with CO in the Presence of Water and Oxygen

Zhiwen Li; Yifei Zhang; Qike Jiang; Liangliang Xu; Zhong-Kang Han; Alfons Baiker; Gao Li

doi:10.1021/acs.langmuir.2c03258

CuCeO_x/CuO Catalyst Derived from the Layered Double Hydroxide Precursor: Catalytic Performance in NO Reduction with CO in the Presence of Water and Oxygen

Langmuir. 2023 May 23;39(20):6957-6963. doi: 10.1021/acs.langmuir.2c03258. Epub 2023 May 10.

Authors

Zhiwen Li^{1

2}, Yifei Zhang³, Qike Jiang¹, Liangliang Xu⁴, Zhong-Kang Han⁵, Alfons Baiker⁶, Gao Li^{1

2}

Affiliations

¹ State Key Laboratory of Catalysis, Dalian Institute of Chemical Physics, CAS, Dalian 116023, China.
² University of Chinese Academy of Sciences, Beijing 100049, China.
³ College of Chemistry and Chemical Engineering, Shenyang Normal University, Shenyang 110034, China.
⁴ Electrical and Biomedical Engineering Multidisciplinary Computational Laboratory, Hanyang University Ringgold Standard Institution, Seoul 04763, Republic of Korea.
⁵ School of Materials Science and Engineering, Zhejiang University, Hangzhou 310027, China.
⁶ Department of Chemistry and Applied Biosciences, Institute for Chemical and Bioengineering, ETH Zurich, Hönggerberg, HCl, CH-8093 Zurich, Switzerland.

PMID: 37162390
DOI: 10.1021/acs.langmuir.2c03258

Abstract

Valencies of metal species and lattice defects, such as oxygen vacancies, play a pivotal role in metal oxide-catalyzed reactions. Herein, we report a promising synthetic strategy for preparing CuO-supported CuCeO_x catalysts (CuCeO_x/CuO) by calcination of a hydrotalcite precursor [Cu₆Ce₂(OH)₁₆]CO₃·nH₂O. The structural and chemical properties of catalysts were characterized by XRD, ICP-AES, TEM, TPR, NH₃-TPD, XPS, Raman spectroscopy, and N₂ adsorption, which revealed that the thermal pretreatment in an oxidative atmosphere caused segregation and reconstitution processes of the precursor, resulting in a mesoporous catalyst consisting of well-dispersed CuO-supported CuCeO_x clusters of 1.8-3.2 nm in size with a high population of oxygen vacancies. The as-prepared catalyst shows excellent catalytic performance in the reduction of NO by CO in the absence as well as in the presence of water and oxygen. This behavior is attributed to its high oxygen defect concentration facilitating the interplay of the redox equilibria between Cu²⁺ and reduced copper species (Cu⁺/Cu⁰) and (Ce⁴⁺/Ce³⁺). The high surface population of oxygen vacancies and in situ-generated metallic copper species have been evidenced by Raman spectroscopy and X-ray photoelectron spectroscopy. The layered double hydroxide-derived CuCeO_x/CuO also showed good water tolerance and long-term stability. In situ infrared spectroscopy investigations indicated that adsorbed hyponitrite species are the main reaction intermediates of the NO conversion as also corroborated by theoretical simulations.