Role of Interfacial Cu‐Ions in Polycrystalline Cu‐CeO 2 : In‐Situ Raman, In‐situ DRIFT and DFT Studies for Preferential Oxidation of CO in Presence of Excess H 2 **

Influence of the Valence of Iron on the NO Reduction by CO over Cu-Fe-Mordenite

A comprehensive study of the catalytic properties of the copper-iron binary system supported on mordenite, depending on the iron valence—CuFe2MOR and CuFe3MOR—was carried out, and redox ability has been considered as a decisive factor in determining catalytic efficiency. Acidity was studied by TPD-NH3, DRIFT-OH, and DRT methods. The total acidity of both samples was high. The Brönsted acidity is similar for both bimetallic samples and is explained by the acidity of zeolite; Lewis acidity varies greatly and depends on the exchange cations. A screening DRIFT study of CO and NO has shown redox capacity and demonstrated a potential for using these materials as catalysts for ambient protection. CuFe2MOR demonstrated stable Cu and Fe species, while CuFe3MOR showed redox dynamic species. As expected, CuFe3MOR displayed higher catalytic performance in NO reduction via CO oxidation, because of the easily reduced intermediate NO-complex adsorbed on the metallic Cu and Fe sites, which were observed through in situ DRIFT study.

Enhancing the bifunctional activity of CoSe2 nanocubes by surface decoration of CeO2 for advanced zinc-air batteries

The coupling of oxygen evolution and reduction reactions (OER and ORR) plays a key role in rechargeable Zn-air batteries (ZABs). However, both OER and ORR still suffer from sluggish kinetics, even when using the mainstream precious metal-based catalysts. Herein, oxygen vacancies-rich CeO₂ decorated CoSe₂ nanocubes are proposed as a novel air electrode to drive OER and ORR for ZABs. The resultant CeO₂ coupled CoSe₂ nanocubes (CeO₂@CoSe₂-NCs) catalyst exhibits a significantly enhanced bifunctional activity relative to the pristine CoSe₂-NCs and the pristine CeO₂. Moreover, an assembled ZABs using this CeO₂@CoSe₂-NCs electrode delivers a high output power density of 153 mW cm^-2 and a long-life stability over 400 cycles, superior to the benchmark Pt/C-IrO₂ electrode. Theoretical calculations reveal that the electronic interaction and oxygen vacancies in CeO₂@CoSe₂-NCs contribute to efficient oxygen electrocatalysis. This protocol provides a promising approach of constructing oxygen vacancies in hybrid catalysts for energy conversion and storage devices.

Reduction-Driven 3D to 2D Transformation of Cu Nanoparticles

The interaction between metal and metal oxides at the nanoscale is of uttermost importance in several fields, thus its enhancement is highly desirable. In catalysis, the performance of the nanoparticles is dependent on a wide range of properties, including its shape that is commonly considered stable during the catalytic reaction. In this study, highly reducible CeO_2-x nanoparticles are synthesized aiming to provide Cu/CeO_2-x nanoparticles, which are classically active catalysts for the CO oxidation reaction. It is observed that the Cu nanoparticles shape changes during reduction treatment (prior to the CO oxidation reaction) from a nearly spherical 3D to a planar 2D shape, then enhances the Cu-CeO_2-x interaction. The spread of the Cu nanoparticles over the CeO_2-x surface during the reduction treatment occurs due to the minimization of the total system energy. The shape change is accompanied by migration of O atoms from CeO₂ surface to the border of the Cu nanoparticles and the change from the Cu⁰ to Cu⁺¹ state. The spreading of the Cu nanoparticles influences on the reactivity results toward the CO oxidation reaction since it changes the local atomic order around Cu atoms. The results show a timely contribution for enhancing the interaction between metal and metal oxide.