催 化 论 坛
『第113期』
Nanoscale Control in Heterogeneous Catalysis
for a Sustainable Future
Professor Emiel Hensen
Eindhoven University of Technology
时间：2024年4月19日（五）9:00
地点：催化楼三楼大会议室
报告摘要：
Efficient utilization of transition metals is one of the most essential requirements for heterogeneous catalysts. Design rules for nanoparticle catalysts are well established and often imply that sub-optimal metal dispersion is desired for high activity. Metal-support interactions can substantially impact the catalytic performance of metal nanoparticles. Specific sites at the metal-support interface can give rise to unusually high activity. In this contribution, I will review structure sensitivity for monometallic and bimetallic catalysts and demonstrate the possibility of tuning metal-support interfaces towards high CeO2 hydrogenation and CO oxidation activity. The approach entails experimental work involving synthesis of uniform active phases, operando characterization, transient kinetic analysis augmented with density functional theory calculations of mechanism, and microkinetics simulations.
The first example deals with approaches to break structure sensitivity. For this, we use cobalt dispersed on ceria-zirconia support materials. We first establish how the size of the support crystallites can stabilize cobalt nanoparticles. Then, we investigate how incomplete cobalt oxide reduction can lead to cobalt-cobalt oxide interfaces with a much higher CeO2 methanation activity than conventional cobalt nanoparticle catalysts. This work shows the promise of tiny metal clusters stabilized on an oxide for achieving high CeO2 methanation activity.
In our second example, we delve deeper into the role of CeO2 crystallites in catalytic reactions. We show how tuning the size of these crystallites can significantly impact the stability and reactivity of single metal atoms. The improved reducibility displayed by CeO2 particles of a few nanometers, as contrasted to bulk CeO2 with a size of tens of nanometers, translates into the retention of single Pd atoms. This retention, in turn, leads to improved kinetics for low-temperature CO oxidation. Our findings highlight the potential of control over the CeO2 crystallite size in enhancing the stability and reactivity of single metal atoms, thereby contributing to the development of more efficient catalysts.
报告人简介：
Emiel Hensen is now the full professor of Inorganic Materials and Catalysis & head of laboratory in Eindhoven University of Technology (TU/e).He is also the Vice-dean of the Department of Chemical Engineering and Chemistry (TU/e) from 2022. He obtained his PhD degree from Eindhoven University of Technology in 2000.
Hensen is the author of more than 600 publications (h-index:100, ~35800 citations). He is the Fellow Chemistry Europe (2024) and Fellow of the Royal Society of Chemistry (2018).He has obtained Veni, Vidi, Vici and TOP grants and is the chairman of the Netherlands Research School for Catalysis (NIOK), board member of the European Research Institute of Catalysis (ERIC) and member of the Advanced Research Center "Chemical Building Blocks Consortium".
The research of Hensen focuses on the fundamental and applied aspects of catalytic materials relevant to clean and sustainable processes for producing energy carriers and chemicals. The working approach is to apply advanced (in situ) characterization methods on as realistic as possible model systems combined with theoretical modeling (density functional theory, microkinetics) and performance testing (kinetics, high-throughput methods, transient techniques) to identify the active sites and their working mechanism. The materials explored include highly structured microporous and mesoporous materials containing reactive centers such as protons, metal ions and metal, metal oxide and metal sulfide clusters and nanoparticles. These materials are used in a wide range of applications, including heterogeneous catalysis (methane activation, CO/CO2 hydrogenation, biomass conversion), electrocatalysis (water electrolysis, CO/CO2 electroreduction, electrochemical synthesis), and photocatalysis (water splitting, CO2 reduction).
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