1,721,324 research outputs found
On the Tracks to “Smart” Single-Atom Catalysts
Full text linkDespite their enormous impact in modern heterogeneous catalysis, single-atom catalysts (SACs) continue to puzzle the catalysis community, which often struggles to draw correct conclusions in SAC-catalyzed experiments. In many cases, the reasons for such an uncertainty originate from the lack of knowledge of the exact single-atom evolution under operative conditions and the fundamental factors controlling the fate of the single atom in relation to the catalytic mechanism. This has led to confusion also about correct definition and terminology, where the coined term single-site catalysts reflects the difficulty in defining the true active species as well as in obtaining long-range ordered homogeneous supports [Chi, S.; et al. J. Catal. 2023, 419, 49-57. DOI: 10.1016/j.jcat.2023.02.003]. Most recent studies have attempted to clarify several of the key aspects that are in play during SAC catalysis. However, one largely overlooked opportunity is to take advantage of all the dynamic phenomena occurring at the single metal site to turn the conventional catalytic sequences into a smart, stimulus-responsive, and controllable evolution of the single atom under operative conditions. Such “smartness” could potentially unleash pathways that mitigate some of the typical drawbacks of SACs, such as selectivity and stability. Here we present our vision on these yet-unexplored opportunities for exploiting the dynamicity of SACs, and we discuss various examples that could be the cornerstones for the advent of a next generation of SACs, that we term here “smart” single-atom catalysts (SSACs). Despite smart-behaving SACs still being far from realization, the clues provided here suggest pathways to achieve this goal
The role of ceria-based nanostructured materials in energy applications
No full textCeria (CeO2) is enjoying increasing popularity in catalytic applications, and in some cases has established itself as an irreplaceable component. The reasons for such success stem from the intrinsic structural and redox properties of ceria. Reducing the ceria particles to the nanoscale has a profound impact on the catalytic behavior. The proliferation of improved synthetic methods that allow control over the final morphology and size of the nano-structures is opening new possibilities in terms of catalytic potential, particularly for energy-related applications
The role of ceria/precious metal interfaces in catalysis
Full text linkThe popularity of ceria (CeO2) supports has been increasing over the last three decades on account of the rich redox chemistry of such an oxide. The ability to act as an oxygen buffer and switch the oxidation state of Ce depending on conditions implies that the role of this oxide goes beyond the conventional function of stabilizing nanoparticles. In fact, ceria can actively participate in catalytic reactions by interacting with the supported metal, in particular precious metals, promoting various types of dynamic processes that are beneficial for catalysis. This perspective put into light such interfacial synergy, and the effects in several catalytic processes, encompassing the most traditional applications up to the most modern reaction schemes
Infrared study of nitric oxide (NO) adsorption and conversion on CeO2-ZrO2 mixed oxide
No full textAn IR study of adsorption of NO- and CO-containing mixtures on a high-surface-area Rh/Ce0.5Zr0.5O2 mixed oxide is reported. At low temperatures, NO strongly interacts with surface oxygen. The presence of various NOx-containing species co-ordinated both to cerium and zirconium has been observed. The NOx storage capacity is mainly associated with the presence of zirconium sites. The extension of NOx storage strongly depends on the adsorption temperature, which is associated with the presence/absence of reactive surface oxygen species. Formation of N2O2- 2 as adsorbed species appears to be a possible key step in the mechanism for conversion of NO at low temperature
Nanostructured materials for advanced automotive de-pollution catalysts
No full textThe present paper reviews the current understanding of CeO 2-ZrO 2 mixed oxides as promoters of the three-way catalysts. Emphasis is given on the role of the synthesis and it is shown that by adopting an appropriate design of the CeO 2-ZrO 2 system, nanostructured materials of high thermal stability can be prepared that are suitable for next generation automotive converter
Structural properties and thermal stability of ceria-zirconia and related materials
No full textThe use of CeO2-based materials in catalysis has attracted considerable attention in recent years, particularly in applications like environmental catalysis, where ceria has shown great potential. This book critically reviews the most recent advances in the field, with the focus on both fundamental and applied issues. The first few chapters cover structural and chemical properties of ceria and related materials, i.e. phase stability, reduction behaviour, synthesis, interaction with probe molecules (CO, O2, NO), and metal-support interaction - all presented from the viewpoint of catalytic applications. The use of computational techniques and ceria surfaces and films for model catalytic studies are also reviewed. The second part of the book provides a critical evaluation of the role of ceria in the most important catalytic processes: three-way catalysis, catalytic wet oxidation and fluid catalytic cracking. Other topics include oxidation-combustion catalysts, electrocatalysis and the use of cerium catalysts/additives in diesel soot abatement technology
Catalysts design for reforming of oxygenates
No full textThis first book to focus on the topic serves as a basis for defining a roadmap for the role of catalysis in energy production. As such, this ready reference for researchers and engineers covers all the hot topics from a broad perspective -- fuel cells, hydrogen production and storage, methane storage and industrial catalysis.
With its analysis of new directions and opportunities in the area and its integration of industrial, governmental and academic points of view, this is a real must-have for everyone interested in "greener" energy production
Hydrogen-Based Technologies for Mobile Applications
No full textHydrogen-based technologies for mobile applications
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