A5019481513- Zeolite Catalysis and Synthesis
- Catalysis and Oxidation Reactions
- Catalytic Processes in Materials Science
- Catalysis and Hydrodesulfurization Studies
- Catalysis for Biomass Conversion
- Catalysts for Methane Reforming
- Metal-Organic Frameworks: Synthesis and Applications
- Mesoporous Materials and Catalysis
- Electrocatalysts for Energy Conversion
- Machine Learning in Materials Science
- Microbial Metabolic Engineering and Bioproduction
- Advanced Chemical Physics Studies
- Ammonia Synthesis and Nitrogen Reduction
- Metal-Catalyzed Oxygenation Mechanisms
- Magnetism in coordination complexes
- Asymmetric Hydrogenation and Catalysis
- Thermochemical Biomass Conversion Processes
- Molecular Junctions and Nanostructures
- Biofuel production and bioconversion
- Plasma Applications and Diagnostics
- Chemical Synthesis and Characterization
- Chemical Synthesis and Reactions
- Oxidative Organic Chemistry Reactions
- Carbon dioxide utilization in catalysis
- Thermal and Kinetic Analysis
University of Minnesota
2016-2025
Indian Institute of Science Bangalore
2024
Voluntary Health Association Of India
2022
University of Minnesota System
2019-2020
Minneapolis Institute of Arts
2016-2019
Twin Cities Orthopedics
2016-2019
University of California, Berkeley
2006-2017
Berkeley College
2017
Lawrence Berkeley National Laboratory
2017
NOAA Chemical Sciences Laboratory
2017
Hierarchical zeolites are a class of microporous catalysts and adsorbents that also contain mesopores, which allow for fast transport bulky molecules thereby enable improved performance in petrochemical biomass processing. We used repetitive branching during one-step hydrothermal crystal growth to synthesize new hierarchical zeolite made orthogonally connected nanosheets. The nanosheets 2 nanometers thick network 0.5-nanometer micropores. house-of-cards arrangement the creates permanent 2-...
The discovery of the dual aromatic- and olefin-based catalytic cycles in methanol-to-hydrocarbons (MTH) catalysis on acid zeolites has given a new context for rationalizing structure–function relationships this complex chemistry. This perspective examines six major chemistries involved hydrocarbon pool mechanism MTH—olefin methylation, olefin cracking, hydrogen transfer, cyclization, aromatic dealkylation—with focus what is known about rate these chemistries. current mechanistic...
A simpler way: Acidic zeolites catalyze dimethyl ether carbonylation to methyl acetate at low temperatures with high selectivity and catalyst stability. This approach provides a halide-free heterogeneous catalytic route acetic acid acetate.
The acid-catalyzed formation of carbon-carbon bonds from C1 precursors via CO insertion into chemisorbed methyl groups occurs selectively within eight-membered ring (8-MR) zeolite channels. This elementary step controls catalytic carbonylation rates dimethyl ether (DME) to acetate. number O-H 8-MR channels was measured by rigorous deconvolution the infrared bands for in cation-exchanged and acid forms mordenite (M,H-MOR) ferrierite (H-FER) after adsorption basic probe molecules varying size....
The extent to which spatial constraints influence rates and pathways in catalysis depends on the structure of intermediates, transition states, active sites involved. We aim answer, as we seek insights into catalytic mechanisms site requirements, persistent questions about potential for controlling selectivities by rational design around within inorganic structures useful catalysts. This Account addresses these matters specific case reactions zeolites that contain Brønsted acid encapsulated...
The acid sites on γ-Al2O3 were characterized using FTIR spectroscopy of adsorbed pyridine and temperature programmed desorption (TPD) 2-propanamine, ethanol, 1-propanol, 2-propanol, 2-methyl-2-propanol, together with density functional theory (DFT) calculations. Following room-temperature adsorption evacuation, the surface coverages alcohols between 2 3.2 × 1018 molecules/m2. For each alcohols, reaction to olefin water products occurred in a narrow peak that indicated is first-order process...
Abstract The selective transformation of light alkanes to aromatics that are more valuable and versatile feedstocks for the chemical industry is one major challenges catalytic chemistry. complexity aromatization chemistry makes it difficult unravel reaction mechanisms and, mechanistic information largely developed from observed product distributions. This article reviews current understanding conversion propane aromatic compounds over HZSM‐5 Ga/HZSM‐5 catalysts based on experimental as well...
Steady state, isotopic, and chemical transient studies of ethanol dehydration on γ-alumina show unimolecular bimolecular reactions are reversibly inhibited by the formation ethanol–water dimers at 488 K. Measured rates ethylene synthesis independent pressure (1.9–7.0 kPa) but decrease with increasing water (0.4–2.2 kPa), reflecting competitive adsorption monomers; while diethyl ether have a positive, less than first order dependence (0.9–4.7 also (0.6–2.2 signifying competition for active...
Vapor phase hydrodeoxygenation (HDO) of furfural over Mo2C catalysts at low temperatures (423 K) and ambient pressure showed high/low selectivity to CO bond/C–C bond cleavage, resulting in 2-methylfuran (2MF) furan ~50–60% <1%, respectively. Efficient usage H2 for deoxygenation, instead unwanted sequential hydrogenation, was evidenced by the 2-methyltetrahydrofuran. The apparent activation energy order 2MF production rates were both found be invariant with conversion caused catalyst...
We highlight the evolution and tunability of catalytic function transition metal carbides under oxidative reductive environments for selective deoxygenation reactions.
Steady state kinetics and measured pyridine inhibition of ethanol dehydration dehydrogenation rates on γ-alumina above 623 K show that can be described with an indirect hydrogen transfer mechanism to form acetaldehyde ethane this proceeds through a shared surface intermediate ethylene synthesis from dehydration. Ethane is produced at rate within experimental error production, demonstrating coproduct dehydrogenation. kinetic measurements indicate are independent co-fed water partial pressure...
Abstract Selectively cleaving the CO bond outside furan ring of furfural is crucial for converting this important biomass‐derived molecule to value‐added fuels such as 2‐methylfuran. In work, a combination density functional theory (DFT) calculations, surface science studies, and reactor evaluation identified molybdenum carbide (Mo 2 C) highly selective deoxygenation catalyst These results indicate potential application Mo C an efficient oxygenates including furanics aromatics.
Single non-heme Fe(II) ions present as structural moieties in several metal–organic frameworks (e.g., MIL-100, MIL-101, and MIL-808, where MIL indicates Materials of Institute Lavoisier) are identified by Kohn–Sham density functional calculations promising catalysts for C–H bond activation, with energetic barriers low 40 kJ mol–1 ethane 60 methane following the oxidative activation iron. The rate-determining step is N2O has a barrier 140 mol–1. Through consideration full reaction profile...
Mesoporous metal carbides are of particular interest as catalysts for a variety reactions because their high surface areas, porous networks, nanosized walls, and unique electronic structures. Here, two ordered mesoporous carbides, Mo2C W2C, were synthesized using nanocasting approach coupled with simultaneous decomposition/carburization process under continuous methane flow. The as-synthesized W2C have three dimensionally structures, large areas (70–90 m2 g–1), crystalline walls. In...