09:30
Unconventional catalyst synthesis and manufacturing methods 3
Chair: Katia Martina
09:30
20 mins
#15
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FIRST GENERATION OF TRANSLUCENT MONOLITHS WITH 3D-PRINTING FOR PHOTOCATALYSIS IN THE VISISBLE LIGHT REGION
Mathias Jacobs, Emine Kayahan, Mumin Enis Leblebici
(presenter: Mathias Jacobs)
Abstract: One promising application of heterogeneous photocatalysis is the photocatalytic oxidation, which can be used to valorize waste glycerol from biodiesel production. Usually a TiO2 catalyst is used convert glycerol to dihydroxyacetone and glyceraldehyde, which can be sold for an order of magnitude more. However TiO2 is optically active in the UV region (λ≤387 nm), therefore it cannot be used for visible photocatalysis. TiO2 can be loaded with gold (plasmonic catalyst) nanoparticles, which improves the quantum yield. The major limitations of heterogeneous photocatalysis are mass and photon transfer limitations. The microreactor proved to solve mentions limitations by providing a high surface area to volume ratio.[1] However, these reactors are difficult to scale-up and therefore have a low throughput. A way to scale-up these reactors is to make use of monolith structures. There were several attempts to use monoliths for photochemistry but they resulted in slow apparent kinetics since monoliths are made of opaque materials.[2] 3D-printing makes it possible to rapidly prototype translucent monoliths.
In this study a 3D-printed unit cell (shown in Figure 1), which is the precursor of the monolith, is constructed and coated with TiO2 gold doped photocatalyst for visible photocatalysis. The unit cell is used to convert waste glycerol. An increase in reaction rate is expected due to the flow regime present in the channels, which eliminates mass transfer limitations.
[1] D. Cambié, C. Bottecchia, N. J. W. Straathof, V. Hessel, and T. Noël, “Applications of Continuous-Flow Photochemistry in Organic Synthesis, Material Science, and Water Treatment,” Chem. Rev., vol. 116, no. 17, pp. 10276–10341, 2016.
[2] J. T. Carneiro, R. Berger, J. A. Moulijn, and G. Mul, “An internally illuminated monolith reactor: Pros and cons relative to a slurry reactor,” Catal. Today, vol. 147, no. SUPPL., pp. 324–329, 2009.
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09:50
20 mins
#82
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CATALYST SUPPORT STRUCTURES WITH IN OPERANDO TUNABLE TRANSPORT PROPERTIES ENABLED BY ADDITIVE MANUFACTURING
Sebastian Trunk, Giang Do, Wilhelm Schwieger, Hannsjörg Freund
(presenter: Hannsjörg Freund)
Abstract: see attached file
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10:10
20 mins
#40
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Experimental investigation of catalytically coated wire cloth micro heat exchangers as methanation reactor
Christian Walter, Ulrich Nieken
(presenter: Christian Walter)
Abstract: Efficient heat dissipation or supply in chemical reactions is critical to achieve desired yields and selectivities. One possible way to efficiently control temperature is to use wire cloth micro heat exchangers. These are open mesh structures consisting of capillary tubes interwoven with wires to form a dense grid structure. Coated with a thin layer of washcoat and catalyst, a high mass transfer with a relatively large surface area can be expected when overflowed with a reaction gas, as illustrated in Figure 1. For an exothermic reaction, the released reaction heat can be effectively transferred to a suitable coolant.
Experimental results for the exothermic methanation of carbon dioxide with hydrogen are presented as an application of the wire cloth micro heat exchanger as a reactor. For this purpose, an experimental reactor tempered with air as coolant was set up in a furnace. In addition, further investigations on heat transfer are shown, such as the investigation on temperature distribution on the mesh shown in Figure 2. Based on these investigations, the possibilities of a heat-integrated reactor concepts are discussed.
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10:30
20 mins
#56
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COMPARISON OF LAYERED MOFs AND STANNOSILICATES AS CATALYSTS FOR THE CONVERSION OF SUGARS TO METHYL LACTATE
Beatriz Murillo, Marta Navarro, Cesar Rubio, Oscar de la Iglesia, Carlos Téllez, Joaquín Coronas
(presenter: Carlos Téllez)
Abstract: Biomass has been shown as an alternative to fossil fuels for obtaining chemical products. The transformation of sugars into methyl lactate (ML) has been carried out with solid catalysts, among others: Sn-MCM-41 and the zeolitic imidazolate framework ZIF-8. Last material belongs to the family of MOFs, very promising materials due to their exceptional properties, namely: specific surface area, adsorption capacity, molecular sieving, organic-inorganic character, possibility of functionalization and control of their properties depending on the ligand and metal selected. On the other hand the layered materials present interesting properties, since they can be exfoliated, which allows obtaining materials that offer greater accessibility to their catalytic sites.
In this work, different laminar materials (UZAR-S4 and ZIF-7-III) were prepared and compared at the ML production from sugars at 160 ºC. UZAR-S4 is a stannosilicate exfoliated material composed of sheets of a few nanometers in thickness and a BET surface of 236 m2/g while the starting stannosilicate UZAR-S3 scarcely adsorbs nitrogen. ZIF-7-III is a 2-D layered MOF formed by the benzimidazolate ligands and Zn atoms which is obtained by contacting ZIF-7 with water. These new catalysts have been characterized by several techniques (XRD, TGA, electron microscopy, BET surface area) before and after the reaction. Exfoliated materials showed valuable and higher ML yields than starting ones. In addition, its reuse in the reaction has been proven, which is an advantage over homogeneous catalysts.
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10:50
20 mins
#96
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An Active and Stable Catalyst for Dry Reforming of Methane via Molecular Layer Deposition
Piyush Ingale, Chengyue Guan, Ralph Kraehnert, Raoul Naumann d`Alnoncourt, Frank Rosowski, Arne Thomas
(presenter: Piyush Ingale)
Abstract: Nickel based catalysts are typically used for the production of synthesis gas by reforming reaction 1. Dry reforming of methane (DRM) is an attractive reaction for production of synthesis gas by reduction of carbon dioxide. However, Ni nanoparticles (NPs) used in DRM reaction suffer from severe coking and sintering at high temperature which leads to decreased activity of the catalyst 2. The challenge is to synthesize a catalyst with a high Ni loading and dispersion
that is stable under reaction conditions.
Molecular Layer Deposition (MLD) is a novel technique, which is a variant of atomic layer deposition. Organic compound replaces H2O as ALD reactant to form purely organic or hybrid inorganic-organic layers 3. In our study, we deposited thin hybrid inorganic-organic layers of alucone on NiO/SiO2 catalyst via alternative reaction of trimethylaluminium and ethylene glycol at 150°C in a fixed bed reactor. The growth behavior of alucone layers on NiO/SiO2 was studied by in-situ mass-gravimetric study. The synthesized catalytic materials were analyzed
by N2 sorption, XPS, XRD, HRTEM and XRF.
The reference and MLD modified catalysts were tested for activity and stability during dry reforming of methane at different temperatures (500°C-800°C). The application of hybrid organic-inorganic alucone layers by molecular layer deposition results in enhanced stability of catalyst under harsh dry reforming conditions while keeping the activity intact.
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