The type of metal-support interactions regulates the electronic structure of catalysts, affecting the intrinsic activity of active sites ( Samantaray et al., 2020). The interaction of these single-atoms with a metal oxide support can be different depending on its environment. Generally, the single atoms are randomly and uncontrollably dispersed on the substrates. The SACs can be defined as a catalyst with isolated single atoms anchored onto its surface, capable of driving a catalytic reaction ( Qiao et al., 2011). Late transition metals that are dispersed at the atomic level are often referred to as single atom catalysts (SACs). The size reduction also benefits the metal-support interactions, this phenomenon stems from the chemical bonding effect between the metal and the supports, as well as the associated interface, along with the charge transfer taking place between metal species and supports ( Yang et al., 2013). There have been reports indicating that active sites often correspond to low coordination sites, such as unsaturated atoms ( Remediakis et al., 2005). The size of metal particle is a critical factor in determining the effectiveness of the catalysts, new findings from both theoretical and experimental studies have shown that clusters with sizes smaller than a nanometer exhibit enhanced catalytic activity and/or selectivity compared to particles of nanometer-scale dimensions ( Herzing et al., 2008 Turner et al., 2008). Considerable endeavors have been dedicated to enhancing the effectiveness of supported metal catalysts downsizing the metal particles ( Yang et al., 2013). Supported metal nanostructures are the most used form of heterogeneous catalyst in the industrial processes. This route offers a promising trajectory towards enhancing catalytic performance across a spectrum of applications and facilitating the discovery of novel chemical reactions.Ĭatalysis plays a central role in shaping our lives, over 90% of all chemical products have at least one catalytic step in their manufacture ( de Vries and Jackson, 2012). Gaining a comprehensive understanding of and optimizing these factors are instrumental in unlocking the full potential of Ir – TiO 2 SACs. ![]() Iridium exhibits superior properties compared to other metals, particularly in maintaining stability as a single atom, owing to its resistance to sintering. A key dimension emphasized in this review is the importance of investigating the iridium-titania system. The review also explores the stability and durability of single-atom catalysts and the importance of understanding their structure-activity relationships to optimize their performance. It discusses the importance, synthesis, characterization techniques such as XPS, STEM, Differential Reflectance Infrared Fourier Transform, and XAS, and the applications of Ir – TiO 2 SACs. This review covers recent developments and frontiers in the particular system of Ir – TiO 2 SACs. By the other hand, titanium oxide is a semiconductor with important applications as a reducible support for different catalyst, widely used in different reactions because of its high activity and stability. In particular, iridium SACs are applied in numerous reactions, from electrocatalytic to photocatalytic applications. SACs consist of isolated metal atoms dispersed on a support material, providing a unique and well-defined atomic structure and composition, allowing for precise control over their properties. Single atom catalysts (SACs) have emerged as a rapidly developing field of catalysis research, with great potential for improving the efficiency and selectivity of many chemical reactions. 2National School of Higher Studies, Morelia Unit, National Autonomous University of Mexico, Morelia, Mexico.1Materials Research Institute, National Autonomous University of Mexico, Mexico City, Mexico.Faraday Trans.1 80(1984) 135-152.Mariana Molina-Torres 1* Orlando Hernández-Cristóbal 2 Ruben Mendoza-Cruz 1* Bomben, Handbook of X-ray Photoelectron Spectroscopy, Perkin-Elmer Corp., Eden Prairie, MN, 1992. Standard Reference Database 20, Version 3.4 (web version) (http://xps/) 2003. Hall also sets the oxide doublet-separation to 3.03 eV. ![]() A second oxide peak may be found in some instances at higher binding energies (61.9-63.7 eV) than seen for IrO2. Ir 4f spectrum of sputter cleaned iridium metal.įrom a quick look at the literature there may be some complex species possible that may complicate the fitting.
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