Lohit Sharma

Bio: Lohit Sharma is an academic researcher from Lehigh University. The author has contributed to research in topics: Catalysis & Dehydrogenation. The author has an hindex of 7, co-authored 12 publications receiving 108 citations.

Oxidative Dehydrogenation of Propane to Propylene with Soft Oxidants via Heterogeneous Catalysis

Abstract: Oxidative dehydrogenation of propane to propylene can be achieved using conventional, oxygen-assisted dehydrogenation of propane (O2–ODHP) or via the use of soft oxidants, such as CO2, N2O, S-conta...

In situ monitoring of mechanochemical synthesis of calcium urea phosphate fertilizer cocrystal reveals highly effective water-based autocatalysis

Abstract: Using the mechanosynthesis of the calcium urea phosphate fertilizer cocrystal as a model, we provide a quantitative investigation of chemical autocatalysis in a mechanochemical reaction. The application of in situ Raman spectroscopy and synchrotron X-ray powder diffraction to monitor the reaction of urea phosphate and either calcium hydroxide or carbonate enabled the first quantitative and in situ study of a mechanochemical system in which one of the products of a chemical reaction (water) mediates the rate of transformation and underpins positive feedback kinetics. The herein observed autocatalysis by water generated in the reaction enables reaction acceleration at amounts that are up to 3 orders of magnitude smaller than in a typical liquid-assisted mechanochemical reaction.

Novel Dual-Action Plant Fertilizer and Urease Inhibitor: Urea·Catechol Cocrystal. Characterization and Environmental Reactivity

Abstract: The mechanochemical reaction of urea and catechol affords the quantitative formation of a 1:1 urea·catechol (URCAT) cocrystal that can act simultaneously as a urease inhibitor and as a soil fertilizer. The novel compound has been characterized using solid-state methods, and its environmental activity has been assessed using the inhibition of Canavalia ensiformis urease and water vapor sorption experiments at room temperature. The urea molecules within the cocrystal were organized in hydrogen-bonded dimers bridged by two catechol molecules, with the OH groups interacting via hydrogen bonds with the urea carbonyl groups. The inhibition of jack bean urease enzyme by URCAT led to the complete loss of urease activity after a 20 min incubation period. A large difference of water vapor adsorption was observed between urea and URCAT, with the latter adsorbing 3.5 times less water than urea. Our results suggested that cocrystal engineering strategies can be successfully applied to tackle sustainability problems at the food–energy–water nexus.

Inhibitor, Co-Catalyst, or Co-Reactant? Probing the Different Roles of H2S during CO2 Hydrogenation on the MoS2 Catalyst

Abstract: Natural gas is often sour, containing varying amounts of H2S and CO2. Gas sweetening processes that are routinely used rely on processes such as amine-based adsorption–desorption cycles, membrane s...

Molecular structure and sour gas surface chemistry of supported K2O/WO3/Al2O3 catalysts

Abstract: Molecular structures of the unpromoted and K2O-promoted supported WO3/Al2O3 catalysts were studied with in situ Raman and UV–vis spectroscopy. In situ Raman spectra revealed that supported 20% WO3/Al2O3 corresponds to near monolayer coverage of isolated and oligomeric surface WOx species on Al2O3. Above monolayer surface WOx coverage (21% WO3/Al2O3), crystalline WO3 nanoparticles are also present. The addition of K2O to the supported WO3/Al2O3 catalyst increased the concentration of isolated surface WOx species and did not form K2WO4 nanoparticles. The reducibility of the tungsten oxide structures depends on their structures (2D or 3D) and the K2O promoter. Their interaction with acidic CO2 and SO2 gases was also investigated. Adsorption of CO2 creates several surface carbonate species of varying acidity that were detected using a combination of in situ IR and mass spectroscopy. Adsorbed bicarbonate form on weakly basic surface sites on tungsten oxide monolayer WO3/Al2O3 catalyst as well as in the presence of low 2.5% K2O loading. At high 5% K2O loading, the presence of the strong surface basic sites yields adsorbed carbonates. After SO2 pretreatment, however, new strongly adsorbed sulfate appears on the surface that inhibits CO2 adsorption.

Sustainability Assessment of Mechanochemistry by Using the Twelve Principles of Green Chemistry.

Abstract: In recent years, mechanochemistry has been growing into a widely accepted alternative for chemical synthesis In addition to their efficiency and practicality, mechanochemical reactions are also recognized for their sustainability The association between mechanochemistry and Green Chemistry often originates from the solvent-free nature of most mechanochemical protocols, which can reduce waste production However, mechanochemistry satisfies more than one of the Principles of Green Chemistry In this Review we will present a series of examples that will clearly illustrate how mechanochemistry can significantly contribute to the fulfillment of Green Chemistry in a more holistic manner

Oxidative Coupling of Methane (OCM) by SiO2-Supported Tungsten Oxide Catalysts Promoted with Mn and Na

Abstract: The literature for the oxidative coupling of methane (OCM) on supported Mn/Na2WO4/SiO2 catalysts is systematically and critically reviewed. The influence of the precursors, starting SiO2 support cr...

Oxidative Dehydrogenation of Propane to Propylene with Soft Oxidants via Heterogeneous Catalysis

Abstract: Oxidative dehydrogenation of propane to propylene can be achieved using conventional, oxygen-assisted dehydrogenation of propane (O2–ODHP) or via the use of soft oxidants, such as CO2, N2O, S-conta...

Direct Mechanocatalysis: Using Milling Balls as Catalysts.

Abstract: Direct mechanocatalysis describes catalytic reactions under the involvement of mechanical energy with the distinct feature of milling equipment itself being the catalyst. This novel type of catalysis features no solubility challenges of the catalysts nor the substrate and on top offering most facile way of separation.