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CeO2‐supported noble metal clusters are attractive catalytic materials for several applications. However, their atomic dispersion under oxidizing reaction conditions often leads to catalyst deactivation. In this study, the noble metal cluster formation threshold is rationally adjusted by using a mixed CeO2‐Al2O3 support. The preferential location of Pd on CeO2 islands leads to a high local surface noble metal concentration and promotes the in situ formation of small Pd clusters at a rather low noble metal loading (0.5 wt %), which are shown to be the active species for CO conversion at low temperatures. As elucidated by complementary in situ/operando techniques, the spatial separation of CeO2 islands on Al2O3 confines the mobility of Pd, preventing the full redispersion or the formation of larger noble metal particles and maintaining a high CO oxidation activity at low temperatures. In a broader perspective, this approach to more efficiently use the noble metal can be transferred to further systems and reactions in heterogeneous catalysis. [ABSTRACT FROM AUTHOR]

The article titled "Highly Active Oxidation Catalysts through Confining Pd Clusters on CeO2 Nano-Islands" published in Angewandte Chemie explores the use of Pd on ceria as a catalytic system for CO oxidation. The authors propose a new approach that involves bringing the noble metal in contact with a strongly interacting nano-island of ceria on alumina. This concept aims to facilitate the formation of active clusters, prevent their dispersion into single atoms, and hinder the sintering of Pd by spatially separating the CeO2 islands. The research involves a collaborative effort by multiple authors. [Extracted from the article]

Pd on ceria, an important catalytic system for various oxidation reactions, is studied for CO oxidationin a Research Article ( e202408511) by Jan- Dierk Grunwaldt et al. The image depicts the new concept of bringing the noble metal in contact with a strongly interacting nano- island ( i. e. ceria) on alumina to 1) facilitate the formation of the active clusters, 2) hinder their redispersion into single atoms, while 3) preventing strong sintering of Pd due to the spatial separation of the CeO2 islands. [Extracted from the article]

A benchmark model that combines an embedded-cluster approach for ionic surfaces with wavefunction-based methods to predict the vibrational frequencies of molecules adsorbed on surfaces is presented. As a representative case, the adsorption of CO on the lowest index non-polar and most stable facet of CeO2, that is, (111) was studied. The CO harmonic vibrational frequencies were not scaled semiempirically but explicitly corrected for anharmonic effects, which amount to about 25 cm-1 with all tested methods. The second-order Møller-Plesset perturbation method (MP2) tends to underestimate the CO harmonic frequency by about 40-45 cm-1 in comparison with the results obtained with the coupled-cluster singles and doubles with perturbational treatment of triple excitation method [CCSD(T)] and independently from the basis set used. The best estimate for the CO vibrational frequency (low-coverage case) differs by 12 cm-1 with the experimental value obtained by infrared reflexion absorption spectroscopy of 1 monolayer CO adsorbed on the oxidized CeO2(111) surface. In addition, a conservative estimate of the adsorption energy of about -0.22 ± -0.07 eV obtained at the CCSD(T) level confirms the physisorption character of the adsorption of CO on the CeO2(111) surface., (© 2024 Author(s). All article content, except where otherwise noted, is licensed under a Creative Commons Attribution (CC BY) license (https://creativecommons.org/licenses/by/4.0/).)

CeO 2 -supported noble metal clusters are attractive catalytic materials for several applications. However, their atomic dispersion under oxidizing reaction conditions often leads to catalyst deactivation. In this study, the noble metal cluster formation threshold is rationally adjusted by using a mixed CeO 2 -Al 2 O 3 support. The preferential location of Pd on CeO 2 islands leads to a high local surface noble metal concentration and promotes the in situ formation of small Pd clusters at a rather low noble metal loading (0.5 wt %), which are shown to be the active species for CO conversion at low temperatures. As elucidated by complementary in situ/operando techniques, the spatial separation of CeO 2 islands on Al 2 O 3 confines the mobility of Pd, preventing the full redispersion or the formation of larger noble metal particles and maintaining a high CO oxidation activity at low temperatures. In a broader perspective, this approach to more efficiently use the noble metal can be transferred to further systems and reactions in heterogeneous catalysis., (© 2024 The Authors. Angewandte Chemie International Edition published by Wiley-VCH GmbH.)