In the context of "270065-1 SE Seminar für Physikalische Chemie und Materialchemie (2021S)":
Quantitative 3D imaging at various length scales for the design of porous catalysts
Dr. Gonzalo Prieto, ITQ Institute of Chemical Technology (CSIC-UPV), Av. Los Naranjos s/n, 46022, Valencia, Spain
Continuous progress in our degree of control over size, morphology and compositional features of porous materials at has led to unprecedented progress in the field of heterogeneous catalysis. Less advanced, however, is our rationale and control over spatial features which can also have a great impact on the ultimate catalytic performance. A first requirement towards this goal is the development of adequate methods to quantify spatial parameters in solid materials. Such methods inevitably need to provide information in the three directions in space, hence beyond the information retrieved with more classical microscopy techniques which project 3D specimens on a single plane, and thus erase the valuable spatial information.This contribution will highlight how different tomographic electron microscopy methods, from electron tomography to FIB-SEM tomography and X-ray microtomography, coupled to quantitative 3D image analysis routines, provide relevant diagnostic means to improve our understanding on spatial features in porous catalysts at various length scales: from the nanometer, to the mesoscopic and micrometer regimes. Topological features of the porous architectures as well as spatial distribution of catalytically active metal species dispersed thereon can determine profoundly performance parameters such as activity, selectivity and stability, and should hence be carefully considered in the process of designing, developing and optimizing advanced solid catalysts and processes.
References:
[1] Nature Materials 12 (2013) 34–39.[2] Angew. Chem. Int. Ed. (2017) 56, 11480.[3] ACS Catal. (2021) 11, 8, 4784–4798. [4] J. Mater. Chem. A (2018) 6, 21978-21989.
Speaker Vita: Chemical engineer by training (University of Oviedo, Spain), Gonzalo Prieto obtained by PhD in chemistry at the Polytechnic University of Valencia (Spain) in 2010. After postdoc stays at Utrecht University (The Netherlands) with Petra and Krijn de Jong(h), and a short visiting stay at Louisiana State University (USA), he received an Alexander von Humboldt personal grant to move to the Max Planck Society (Germany), where in 2015 he was appointed group leader at the Heterogeneous Catalysis Department of the Max Planck Institut für Kohlenforschung, headed by Prof. Ferdi Schüth. In 2018, Prieto accepted a senior tenured researcher position at the Spanish Research Council (CSIC), and moved the group to the Institute of Chemical Technology (ITQ, Valencia, Spain), a Severo Ochoa Excellence Research Center active in the field of catalysis. The research interests of Gonzalo Prieto’s group are on heterogeneous catalysis for the selective conversion of small molecules such as CH4 and light alka/enes, CO2, CO (in syngas) etc into commodity chemicals and fuels. To date, Prieto has published about 50 scientific articles in the fields of materials science and catalysis (Nature Materials, Nature Commun. Angew. Chem., JACS, ACS Catalysis, J. Catal., etc, >4500 citations) and 6 book chapters. In addition, his research has led to 6 patents/patent applications, three of which are transferred to industry. Prieto has managed/currently manages 15 public funded research projects as principal investigator in three different countries, including the ERC Consolidator grant TANDEng supported by the European Research Council.
Bridging the gap between heterogeneous and homogeneous photocatalysis
Dr. Alexey Cherevan, Institut für Materialchemie E165, Getreidemarkt 9/BC/02/A18, TU Wien, Austria, alexey.cherevan@tuwien.ac.at
Due to the ongoing global warming and the upcoming energy crises, the exploitation of alternative, renewable energy sources has become a major focus of materials chemistry. The ultimate solution for sustainable energy lies in the concept of solar fuels – commodity chemicals that can be generated from nothing but sunlight and abundant feedstock through heterogeneous photocatalysis. The reactions of water splitting and carbon dioxide photoreduction, however, involve complex multi-electron redox processes that require a rational design of the surface catalytic sites. When working with ill-defined inorganic surfaces, these sites are inevitably hard to study and understand on a truly fundamental level, which limits the development of active and selective photocatalysts. The field of homogeneous photocatalysis has been evolving independently from its heterogeneous branch, however, it has been much more successful in the purposeful design of organometallic (photo)catalysts assisted by the concepts of coordination chemistry. Molecular photocatalysts, however, face a different set of challenges related to their insufficient redox stability and the need for a molecular photosensitizer required to accomplish the absorption step.In this talk, I will introduce both the fields and demonstrate a few examples of our research work that cover heterogeneous and homogeneous approaches to photocatalysis. On one hand, I will talk about the design of earth-abundant co-catalysts for photocatalytic water splitting; on the other hand, I will show our work with molecular metal oxides for visible-light-driven water oxidation. These examples will highlight the advantages but also the limitations of both fields. Finally, I will show that a rational combination of both approaches to photocatalysis can address their challenges and help bridging the gap between the communities.
Alexey Cherevan is currently a junior research group leader at the Institute of Materials Chemistry at TU Wien, Austria. He obtained his Master's Degree from Moscow State University, Russia in 2010 and received his PhD from The University of Münster, Germany in 2014. After a short postdoctoral training, in November 2015, he joined the TU Wien to pursue his habilitation. His interests revolve around materials chemistry and functional inorganic nanomaterials for a variety of energy-related applications. More recently, he develops novel tools towards a combination of heterogeneous and homogeneous fields of photocatalysis.
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