A5007927950- Catalytic Processes in Materials Science
- Catalysis and Oxidation Reactions
- Catalysts for Methane Reforming
- CO2 Reduction Techniques and Catalysts
- Metal-Organic Frameworks: Synthesis and Applications
- Carbon dioxide utilization in catalysis
- Nanomaterials for catalytic reactions
- Electrocatalysts for Energy Conversion
- Ammonia Synthesis and Nitrogen Reduction
- Zeolite Catalysis and Synthesis
- Advanced Photocatalysis Techniques
- Machine Learning in Materials Science
- Catalysis for Biomass Conversion
- Catalysis and Hydrodesulfurization Studies
- Analytical chemistry methods development
- Electrochemical Analysis and Applications
- Analytical Chemistry and Sensors
- X-ray Diffraction in Crystallography
- Catalytic Cross-Coupling Reactions
- Topological Materials and Phenomena
- Hydrogen Storage and Materials
- Mesoporous Materials and Catalysis
- Arsenic contamination and mitigation
- Advanced Battery Materials and Technologies
- Oxidative Organic Chemistry Reactions
Leibniz Institute for Catalysis
2021-2024
Universität Ulm
2012-2023
Cairo University
2009-2023
Robert Bosch (Germany)
2023
Single-atom catalysts are often considered as the ultimate design principle for supported catalysts, due to their unique geometric and electronic properties highly efficient use of precious materials. Here, we report a single-atom catalyst, Cu/UiO-66, prepared by covalent attachment Cu atoms defect sites at zirconium oxide clusters metal-organic framework (MOF) UiO-66. Kinetic measurements show this catalyst be active stable under realistic reaction conditions two important test reactions,...
Aiming at a detailed understanding of the role metal–support interactions in selective methanation CO CO2-rich reformate gases, we have investigated catalytic performance set Ru/TiO2 catalysts with comparable Ru loading, particle size, and TiO2 phase composition but very different surface areas (ranging from 20 to 235 m2 g–1) this reaction. The activity for methanation, under steady-state conditions, was found strongly depend on support area, increasing first area up maximum catalyst 121 g–1...
Abstract Ru/TiO 2 catalysts exhibit an exceptionally high activity in the selective methanation of CO ‐ and H ‐rich reformates, but suffer from continuous deactivation during reaction. This limitation can be overcome through fabrication highly active non‐deactivating by engineering morphology TiO support. Using anatase nanocrystals with mainly {001}, {100}, or {101} facets exposed, we show that after initial activation period ‐{100} ‐{101} are very stable, while ‐{001} deactivates...
Ru/Al2O3 is a highly stable, but less active catalyst for methanation reactions. Herein we report an effective approach to significantly improve its performance in the of CO2/H2 mixtures. Highly and stable Ru/γ-Al2O3 catalysts were prepared by high-temperature treatment reductive reaction gas. Operando/in situ spectroscopy STEM imaging reveals that strongly improved activity, factors 5 14 CO CO2 methanation, accompanied flattening Ru nanoparticles formation basic hydroxylated alumina sites....
Abstract The electronic and structural properties of Au/ZnO under industrial idealized methanol synthesis conditions have been investigated. This was achieved by kinetic measurements in combination with time‐resolved operando infrared (DRIFTS) as well situ near‐ambient pressure X‐ray photoelectron spectroscopy (NAP‐XPS) absorption near‐edge (XANES) at the O K‐edge together high‐resolution electron microscopy. adsorption CO during reaction revealed presence negatively charged Au...
In a systematic approach to control and improve the performance of Au/ZnO catalysts in methanol synthesis from CO2, we have studied effect varying ZnO particle size. We show that with increasing size (22–103 nm), while keeping Au loading/Au constant, activity for formation passes through maximum volcano-shaped relation, selectivity increases steadily. This is explained by an electronic modification interface perimeter sites, due metal–support interactions (EMSIs), which occur together...
Elucidating the reaction mechanism in heterogeneous catalysis is critically important for catalyst development, yet remains challenging because of often unclear nature active sites. Using a molecularly defined copper single-atom supported by UiO-66 metal-organic framework (Cu/UiO-66) allows detailed mechanistic elucidation CO oxidation reaction. Based on combination situ/operando spectroscopies, kinetic measurements including isotope effects, and density-functional-theory-based calculations,...
Ru/TiO2 catalysts are highly active and selective in the methanation of CO presence large amounts CO2 but suffer from a considerable deactivation loss selectivity during time on stream. Aiming at fundamental understanding these processes, we have systematically investigated physical reasons responsible for effects, using with different surface areas combining time-resolved kinetic situ/operando spectroscopy measurements as well ex situ catalyst characterization. This allowed us to identify...
Operando XAS measurements in the near (XANES) and extended (EXAFS) Au LIII edge as well situ diffuse reflectance FTIR (DRIFTS) spectroscopy were employed combination with kinetic a further attempt to identify nature of active species responsible for high activity Au/CeO2 catalyst low-temperature water gas shift (LT-WGS) reaction. The changes reaction behavior during LT-WGS followed at 180 °C different initial states catalyst, prepared by either reducing or oxidizing pretreatments...
Aiming at a mechanistic understanding of the methanol (MeOH) synthesis from CO2/H2 over Au/CeO2 catalysts and activation/deactivation these catalysts, we have investigated processes by combination kinetic measurements, time-resolved in situ diffuse reflectance Fourier transform infrared (FTIR) spectroscopy (DRIFTS) structural characterization X-ray diffraction (XRD) scanning transmission electron microscopy (STEM). Kinetic measurements indicated rapid activation phase, followed continuous...
Cu single-atom catalysts (SACs) supported on CeO2–TiO2 were prepared by a sol–gel method and tested for CO oxidation between 120 350 °C. Operando in situ spectroscopic methods including diffuse reflectance infrared Fourier transform (DRIFT), electron paramagnetic resonance (EPR), near ambient pressure X-ray photoelectron spectroscopy (NAP-XPS) combined with other basic characterizations applied to identify active sites derive reliable structure–reactivity relationships. Rising the content...
Catalytic partial oxidation of methane presents a promising route to convert the abundant but environmentally undesired gas liquid methanol with applications as an energy carrier and platform chemical. However, outstanding challenge for this process remains in developing catalyst that can oxidize selectively good activity under continuous flow conditions phase using O2 oxidant. Here, we report Fe supported by metal-organic framework (MOF), Fe/UiO-66, selective on-stream methanol. Kinetic...
The selectivity for CO methanation is a decisive aspect the practical application of reaction removal from CO2-rich H2 fuel gases produced via hydrocarbon reforming. We show that increasing water content in feed gas, up to technically relevant levels 30%, significantly increases supported Ru catalysts compared with operation (almost) dry while operando EXAFS measurements reveal gradual decrease particle size amounts gas feed. Consequences these findings and related IR spectroscopic data...
The impact of CO on the activation and reaction characteristics Au/ZnO catalysts in methanol synthesis from a CO2/H2 mixture was studied by kinetic, near ambient pressure X-ray photoelectron spectroscopy absorption at O K-edge, together with situ Foureir transform infrared measurements. Transient measurements under up to industrial conditions (50 bar, 240 °C) show pronounced transient increase activity for formation after exposure CO/H2 gas mixture, while steady-state is similar that...
Hydrogenation of CO2 is very attractive for transforming this greenhouse gas into valuable high energy density compounds. In work, we developed a highly active and stable Ru/TiO2 catalyst methanation prepared by solgel method that revealed much higher activity in (ca. 4–14 times turnover frequencies at 140–210°C) than state-of-the-art catalysts control sample wetness impregnation. This attributed to concentration O-vacancies, inherent the methodology, which play dual role 1) activation 2)...
Abstract Hydrogen storage materials and technologies are deemed as the cornerstone towards a world economy less reliant on, ultimately independent of fossil resources. Ammonia is considered among most efficient carbon‐free hydrogen carriers because its relatively high gravimetric volumetric capacities and, equally important, ease transport storage. In addition, well‐established chemical production ammonia (preferably green Haber‐Bosch process) would accelerate immediate introduction into...