Manipulating Copper Dispersion on Ceria for Enhanced Catalysis: A Nanocrystal‐Based Atom‐Trapping Strategy

Abstract

Due to tunable redox properties and cost-effectiveness, copper-ceria (Cu-CeO 2 ) materials have been investigated for a wide scope of catalytic reactions. However, accurately identifying and rationally tuning the local structures in Cu-CeO 2 have remained challenging, especially for nanomaterials with inherent structural complexities involving surfaces, interfaces, and defects. Here, a nanocrystal-based atom-trapping strategy to access atomically precise Cu-CeO 2 nanostructures for enhanced catalysis is reported. Driven by the interfacial interactions between the presynthesized Cu and CeO 2 nanocrystals, Cu atoms migrate and redisperse onto the CeO 2 surface via a solid-solid route. This interfacial restructuring behavior facilitates tuning of the copper dispersion and the associated creation of surface oxygen defects on CeO 2 , which gives rise to enhanced activities and stabilities catalyzing water-gas shift reaction. Combining soft and solid-state chemistry of colloidal nanocrystals provide a well-defined platform to understand, elucidate, and harness metal-support interactions. The dynamic behavior of the supported metal species can be further exploited to realize exquisite control and rational design of multicomponent nanocatalysts.

Modulating the water gas shift reaction via strong interfacial interaction between a defective oxide matrix and exsolved metal nanoparticles

“…First, we identified the exact reaction starting temperature by TPSR experiments. The reaction mechanism can be identified according to the difference in the product's production temperature: if the temperatures of two products (H 2 and CO 2 ) differ, it can be thought that the reaction occurs via the redox mechanism 68 because in the redox mechanism, H 2 and CO 2 production occurs independently, unlike in the associative mechanism. In this study, CO and H 2 O were simultaneously injected, and mass spectrometry detected the products.…”

Nonclassical Strong Metal–Support Interactions for Enhanced Catalysis

“…For instance, calcinating the physical mixture of presynthesized Cu and CeO 2 nanocrystals induces copper detachment from the nanoparticles; migration at the CuO/CeO 2−x solid−solid interface; and redispersion and stabilization on the ceria surface as single atoms, clusters, and nanoparticles. 72 The copper/ceria interface is visualized as a bilayer architecture, with the bottom layer in the form of Cu + −O v −Ce 3+ and the top one mainly consisting of Cu 0 atoms. 20 This allows quantitative optimization of the copper and oxygen defect sites that account for the activation of CO and H 2 O molecules, respectively, collectively catalyzing the water−gas shift reaction (WGSR).…”

In Situ Electrochemical Reconstitution of CF–CuO/CeO2 for Efficient Active Species Generation

“…The industrialization of electrocatalysis is one of the most promising ways to achieve a sustainable supply of high-value-added chemicals and reduce the use of fossil fuels. − In the field of electrocatalysis, it is generally believed that the insufficient activity and poor selectivity and stability of electrocatalysts are the biggest obstacles to the industrialization of electrocatalytic technology, which motivates researchers to solve this criticism through the construction of electrode materials, optimization of electrolytes, design of electrolytic cells, and other approaches. − However, most of the current research mainly focuses on exploring new complicated materials to construct electrocatalysts, conversely ignoring the fundamental insight of the correlation between the intrinsic nature of the material and catalytic activity . In fact, most non-noble metal catalysts, especially transition metal oxides, exhibit satisfactory electrocatalytic activity under an efficient electrochemical reconfiguration. − Apparently, in situ electrochemical activation can optimize the chemical composition and electronic structure of a catalyst, prompting the exposure of more active sites, thereby further enhancing the electrocatalytic performance. In other words, the active site is generally not a component of the original synthetic catalyst but is often a new species generated after electrochemical activation. , Therefore, how to directly target the active sites of a catalyst and deeply understand the catalytic mechanism of the active species are the keys to the current catalyst design. − …”