Engineering topics

York, Allyson

Publications and source records attributed to York, Allyson.

3 records

DOE OSTI2022

MgO(111) Nanocatalyst for Biomass Conversion: A Study of Carbon Coating Effects on Catalyst Faceting and Performance

Solid base metal oxide catalysts such as MgO offer utility in a wide variety of syntheses from pharmaceuticals to fuels. The (111) facet of MgO shows enhanced, unique properties relative to the other facets. Carbon coatings have emerged as a promising modification to impart metal oxide catalyst stability. Here, we report the synthesis, characterization, and catalytic properties of commercial MgO, MgO(111), and carbon coated derivatives thereof for 2-pentanone condensation. The dimer and trimer products of this reaction can be used as precursors for biofuels upon oxygen removal and thus have relevance in environmental sustainability. Additionally, MgO(111) maintained impressive selectivity towards the dimer product after carbon coating, whereas the other catalysts experienced a decrease in conversion and selectivity as a consequence of the carbon coating. Our findings highlight the catalytic efficacy of MgO(111), provide insight into carbon coating for catalyst stability, and pave the way for continued mechanistic investigations.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗

DOE OSTI2019

Methyl Ketone Condensation over Tailored Metal Oxides

Methyl ketones represent promising oxygenate intermediates that can be derived from lignocellulosic biomass via numerous conversion routes and subsequently coupled to produce precursors for renewable diesel and aviation fuels. Basic metal oxides are known to promote ketone coupling via condensation reactions, with magnesium oxide (MgO) providing an ideal catalytic system for evaluating the reaction mechanism and role of water on observed activity. Recent studies demonstrate that the MgO(111) surface facet can be promoted to enhance activity for base catalyzed reactions; however, to our knowledge, there is a dearth of information regarding the impact of MgO(111) faceting and surface termination under reaction conditions for ketone coupling. Therefore, this talk will discuss our recent investigation into the catalytic coupling of methyl ketones over MgO(100) and MgO(111) catalysts. Results will be presented that address the synthesis and detailed characterization of MgO(111) nanosheets, as well as their activity and selectivity for ketone coupling when compared to MgO(100). The impact of water on MgO surface termination will be discussed, as well as a proposed reaction mechanism for ketone condensation over clean and hydroxyl terminated surfaces for both facets. Findings will include outcomes from experimental studies, computational modeling, and advanced surface characterization by neutron scattering. Collectively, this work provides further insight into the role of tailored metal oxide catalysts for this important class of biomass conversion chemistry.

09 BIOMASS FUELS↗

DOE OSTI2019

Enhanced Catalyst Durability for Bio-Based Adipic Acid Production by Atomic Layer Deposition

Harsh reaction environments challenge the lifetime productivity of conventional catalysts and impede emerging biobased chemical processes. Condensed-phase processing of muconic acid, a biobased platform chemical, leads to problematic levels of catalyst leaching and fouling. Atomic layer deposition (ALD) can improve catalyst durability using protective metal oxide coatings; however, a targeted coating strategy and cost models thereof are needed for application-specific deactivation challenges that can surmount these challenges while accounting for process implications. Herein, we utilize thin (<5 wt% Al) Al2O3 ALD coatings to increase the lifetime productivity of Pd/TiO2 during muconic acid hydrogenation to adipic acid. The ALD coating decreases Pd leaching by >3x and markedly improves the thermal stability of Pd and TiO2. Economic analysis for an adipic acid biorefinery supports that increased material costs and reduced catalyst productivity can be justified through lifetime extension. Broadly, this work lays the foundation for reducing the cost of biobased chemical processes through catalyst stability.

Settle, Amy↗