Author: W. Wilson McNeary
Publisher:
ISBN:
Category : Atomic layer deposition
Languages : en
Pages : 0

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Author: W. Wilson McNeary
Publisher:
ISBN:
Category : Biomass energy
Languages : en
Pages : 1

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Author:
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Category :
Languages : en
Pages : 0

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Book Description
This CRADA will facilitate technology maturation for NREL-developed ALD-coated catalyst materials that are tailored for durability during harsh biomass conversion chemistries. This project will address optimizing process parameters for scale-up of Al2O3 ALD-coated catalysts, demonstrating ALD-coated catalyst performance for muconic acid hydrogenation, and validating economic models that project significant cost benefits for ALD-enhanced catalytic processes. This work will strengthen private-public partnerships in the area of advanced catalyst manufacturing for energy-related technology. Critical information will be collected to elevate the Technology Readiness Level and increase our competitiveness for cooperative R&D agreements and licensing. Success of this work will be crosscutting as it can facilitate advanced catalyst development for both renewable and conventional processes.

Author: Derek Vardon
Publisher:
ISBN:
Category : Biomass conversion
Languages : en
Pages : 9

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Author:
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ISBN:
Category :
Languages : en
Pages : 22

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Atomic layer deposition (ALD) has emerged as an interesting tool for the atomically precise design and synthesis of catalytic materials. Herein, we discuss examples in which the atomic precision has been used to elucidate reaction mechanisms and catalyst structure-property relationships by creating materials with a controlled distribution of size, composition, and active site. We highlight ways ALD has been utilized to design catalysts with improved activity, selectivity, and stability under a variety of conditions (e.g., high temperature, gas and liquid phase, and corrosive environments). In addition, due to the flexibility and control of structure and composition, ALD can create myriad catalytic structures (e.g., high surface area oxides, metal nanoparticles, bimetallic nanoparticles, bifunctional catalysts, controlled microenvironments, etc.) that consequently possess applicability for a wide range of chemical reactions (e.g., CO2 conversion, electrocatalysis, photocatalytic and thermal water splitting, methane conversion, ethane and propane dehydrogenation, and biomass conversion). Lastly, the outlook for ALD-derived catalytic materials is discussed, with emphasis on the pending challenges as well as areas of significant potential for building scientific insight and achieving practical impacts.

Author:
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Category :
Languages : en
Pages : 0

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This CRADA advanced the use of atomic layer deposition (ALD) catalyst coatings to improve sulfur tolerance and demonstrate improved catalyst durability for biomass conversion chemistries. This project leveraged National Laboratory and industry expertise for ALD catalyst coating development between NREL, ALD NanoSolutions, Inc. ("ALD NanoSolutions"), and Johnson Matthey PLC ("Johnson Matthey"). To better understand the role of ALD coatings on catalyst activity and durability, a joint experimental and computational effort combined bench-scale ALD catalyst synthesis, material characterization, catalyst testing, and modeling of catalyst surface energetics. In addition, to demonstrate the commercial relevance of this technology, scaled ALD coated catalysts were subjected to continuous testing and accelerated aging to validate performance gains. Results were used to inform ALD catalyst coating manufacturing cost models, as well as biobased chemical process cost models.

Author:
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Category :
Languages : en
Pages : 0

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Robust heterogeneous catalysts are essential for enabling biomass conversion; however, harsh reaction environments introduce durability challenges for many conventional catalyst materials [1]. The hydrogenation of biobased muconic acid to adipic acid is one such emerging chemistry that faces PGM catalyst stability challenges [2]. Muconic acid is a heavily-investigated biobased platform chemical that can be converted into an array of large-market commodity chemicals [2]. PGM catalysts are exceptionally effective for muconic acid hydrogenation to adipic acid, with Pd the most active to date. [2] However, Pd leaches in an acidic environment and this chemistry has a high propensity for fouling. Atomic layer deposition (ALD) is one such material design strategy that has emerged to stabilize supported metal catalysts [3]. ALD coatings are theorized to stabilize supported metal active sites by i) covering high-energy facets most susceptible to degradation, ii) disrupting the physical mobility of active sites, and iii) reinforcing the structure of the underlying catalyst support [3]. However, ALD coatings for catalyst durability with carboxylic acids remains an underdeveloped area of research and literature reports have yet to consider the techno-economic tradeoffs between the ALD manufacturing cost and catalyst lifetime productivity. This study examines low-cycle Al2O3 ALD coatings to stabilize Pd/TiO2 against deactivation during muconic acid hydrogenation. The unique harshness of muconic acid for Pd leaching was evaluated by both experiment and computation. Based on batch reactor screening results, uncoated and ALD coated catalysts were evaluated in a continuous flow reactor for their productivity, stability, and post-reaction regenerability at 700 degrees C. Characterization was performed to assess the impact of ALD coatings on catalyst morphology, as well as following regeneration. Finally, techno-economic analysis models evaluated the value proposition for ALD-coated catalysts within an nth-generation adipic acid biorefinery.

Author: Derek Vardon
Publisher:
ISBN:
Category : Atomic layer deposition
Languages : en
Pages : 0

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Author:
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Category :
Languages : en
Pages : 0

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Increases in the cost of fossil fuels along with growing concerns for greenhouse gas emissions are prompting the search for renewable sources of liquid fuel and chemicals. Biomass has been considered as the only realistic and sustainable source of renewable organic carbon for the foreseeable future. Heterogeneous catalysis has played an important role in the development of efficient chemical processes to convert biomass to fuels and chemicals. In this respect, the design of inexpensive active and stable heterogeneous catalysts is important to develop new and improved processes for the conversion of biomass. This dissertation focuses on aqueous-phase hydrodeoxygenation (APHDO) and aqueous-phase hydrogenation (APH) as model reactions to design improved supported metal catalysts for the conversion of biomass-derived feedstocks. Both APHDO and APH are crucial in converting biomass-derived compounds into liquid fuels and chemicals. In this dissertation, the activity of a number of monometallic and bimetallic catalysts is compared for APH of carbonyl compounds which is an important reaction in APHDO. Bimetallic Pd-Fe is the most active catalyst among the tested catalysts for APH of C=O and C=C bonds. APHDO of sorbitol was performed with the bimetallic Pd-Fe supported on zirconium phosphate (Zr-P). Zr-P was chosen as the support due to its high Brønsted to Lewis acid ratio and stability in the aqueous phase. The Pd1Fe3/Zr-P catalyst is up to 14 times more active than monometallic Pd/Zr-P and Pt/Zr-P catalysts. Moreover, the Pd1Fe3/Zr-P catalyst produces more C4-C6 products by promoting the conversion of sorbitan and isosorbide and more C1-C3 products by promoting C-C bond cleavage (dehydrogenation/retro-aldol condensation) of sorbitol. Another critical issue of designing heterogeneous catalysts for aqueous-phase reactions is stability of the catalysts. A method for stabilizing base-metal particles of a Co/TiO2 catalyst is developed using atomic layer deposition (ALD) of TiO2 film onto the surface of the Co/TiO2 catalyst. The ALD TiO2 coated Co/TiO2 catalyst was tested for APH reactions in a continuous flow reactor and characterized using chemisorption, surface area analysis, electron microscopy, X-ray diffraction, and small-angle X-ray scattering. Through these techniques, it is shown that the ALD TiO2 coating protects the cobalt particles against leaching and sintering under aqueous conditions. High-temperature treatments of a Co/TiO2 catalyst cause migration of partially reduced TiO2 onto cobalt particles caused by strong metal-support interaction (SMSI) between cobalt and TiO2. The SMSI effect in the Co/TiO2 catalyst is elucidated using in situ Raman spectroscopy and electron microscopy. By the SMSI effect, cobalt particles of the Co/TiO2 catalyst are decorated by TiOx (x 2) species. The TiOx decoration stabilizes the cobalt particles in a similar way to ALD TiO2 overcoating. The SMSI effect also creates a bifunctional catalytic site in the Co/TiO2 which facilitates a furanyl ring-opening reaction. The high-temperature treated Co/TiO2 catalyst had 95 % yield for APH of carbonyl compounds to their corresponding alcohols. The two methods for stabilizing cobalt catalysts introduced in this dissertation, ALD and SMSI, may enable the replacement of expensive novel-metal catalysts with inexpensive base-metal catalysts for aqueous-phase conversion of biomass-derived feedstocks.

Author: David Cameron
Publisher: MDPI
ISBN: 3039366521
Category : Science
Languages : en
Pages : 142

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Atomic layer deposition (ALD) is a thin film deposition process renowned for its ability to produce layers with unrivaled control of thickness and composition, conformability to extreme three-dimensional structures, and versatility in the materials it can produce. These range from multi-component compounds to elemental metals and structures with compositions that can be adjusted over the thickness of the film. It has expanded from a small-scale batch process to large scale production, also including continuous processing – known as spatial ALD. It has matured into an industrial technology essential for many areas of materials science and engineering from microelectronics to corrosion protection. Its attributes make it a key technology in studying new materials and structures over an enormous range of applications. This Special Issue contains six research articles and one review article that illustrate the breadth of these applications from energy storage in batteries or supercapacitors to catalysis via x-ray, UV, and visible optics.