Simon G. Podkolzin

• Ph.D. Chemical Engineering
• Professor (Associate) at Stevens Institute of Technology

Direct methane conversion into aromatic hydrocarbons over catalysts with molybdenum (Mo) nanostructures supported on shape-selective zeolites is a promising technology for natural gas liquefaction. We determined the identity and anchoring sites of the initial Mo structures in such catalysts as isolated oxide species with a single Mo atom on aluminu...

Acetylene reactivity as a function of Sn concentration on Pt catalytic surfaces was studied by comparing adsorption and reactions of regular and deuterated acetylene at 90–1000 K on three surfaces, Pt(111), Pt3Sn/Pt(111), and Pt2Sn/Pt(111), using high-resolution electron energy loss spectroscopy, temperature-programmed desorption, and density funct...

Vibrational spectroscopic measurements and density functional calculations were used to identify a preferential catalytic mechanism for the transformation of acetylene, HCCH, to vinylidene, CCH2 , on surfaces of Pt-Sn ordered alloys. In this mechanism, two adjacent Pt atoms adsorb an acetylene molecule and a third neighboring Pt atom is required...

Mo carbide nanoparticles supported on ZSM-5 zeolites are promising catalysts for methane dehydroaromatization. For this and other applications, it is important to identify the structure and anchoring sites of Mo carbide nanoparticles. In this work, structures of Mo2Cx (x = 1, 2, 3, 4, and 6) and Mo4Cx (x = 2, 4, 6, and 8) nanoparticles are identifi...

A novel Mg-based bimetal reagent (Mg/Cu) was used as an enhanced reductive system to degrade insensitive munition 2,4-dinitroanisole (DNAN), a contaminant found in energetic-laden waste. Degradation of DNAN was significantly impacted by dissolved oxygen and studied in anoxic and oxic bimetal systems (i.e., purging with N2, air, or O2 gas). Degradat...

The O-H stretching vibration of surface hydroxyls remained at 3691 cm-1 for gold structures ranging in size from clusters to nanoparticles, to non-flat bulk surfaces. In contrast, this vibration was...

Acetic acid adsorption and reactions at multiple surface coverage values on Ni(110) were studied with temperature programmed desorption (TPD) and infrared reflection absorption spectroscopy (IRAS) at 90-500 K. The experimental measurements were interpreted with density functional theory (DFT) calculations that provided information on adsorbate geom...

Guaiacol (2-methoxyphenol, C6H4(OH)(OCH3)) adsorption and reactions on a Pt(100) surface were studied with infrared reflection-absorption spectroscopy (IRAS) and temperature programmed desorption (TPD) measurements at different surface coverage values from 100 to 800 K. In addition, density functional theory (DFT) calculations were used to determin...

Reaction rates for H2O2 decomposition in a methanol solution were measured over Pd/SiO2 catalysts in the presence of gas-phase N2, H2 and propylene. The H2O2 decomposition rates were higher in the presence of H2 and lower in the presence of propylene compared to those under N2, which acted as an inert gas. For interpretation of the experimental res...

Adsorption of trans-1,2-bis(4-pyridyl)ethylene (BPE), a molecule with two pyridine rings connected with a C=C double bond, was studied on Ag surfaces with surface-enhanced Raman spectroscopic (SERS) measurements and density functional theory (DFT) calculations. Spectroscopic measurements were collected using well-defined 48 nm monodispersed Ag and...

Cr/ZSM-5 catalysts with 0.5-2.6 wt % Cr loadings and zeolites with 15-140 Si/Al ratios were characterized with in situ UV-vis, IR, and Raman spectroscopies, including operando Raman measurements under reaction conditions in methane conversion at 773-1123 K with a simultaneous online analysis of reaction products. DFT calculations with cluster and p...

A new type of material, a "nanobursa" mesh (from "bursa" meaning "sac or pouch"), is introduced. This material consists of sequential layers of porous polymeric nanofibers encapsulating carbon nanotubes, which are functionalized with different metal nanoparticles in each layer. The nanobursa mesh is fabricated via a novel combination of twin-screw...

Oxidatively halogenate methane by placing a feedstream that comprises methane, a source of halogen, a source of oxygen and, optionally, a source of diluent gas in contact with a first catalyst (e.g. a solid super acid or a solid super base) that has greater selectivity to methyl halide and carbon monoxide than to methylene halide, trihalomethane or...

Heterogeneous catalysis is a critical component in the improvement of existing technologies and development of new solutions in the area of clean energy and sustainability. Combining vibrational spectroscopies with quantum chemical calculations can provide molecular-level information on the structure of catalytic surfaces and reaction pathways. As...

The present disclosure provides a process and a system for producing dichlorine (Cl2).

Adsorption and decomposition of cyclohexanone (C(6)H(10)O) on Pt(111) and on two ordered Pt-Sn surface alloys, (2 × 2)-Sn/Pt(111) and (√3 × √3)R30°-Sn/Pt(111), formed by vapor deposition of Sn on the Pt(111) single crystal surface were studied with TPD, HREELS, AES, LEED, and DFT calculations with vibrational analyses. Saturation coverage of C(6)H(...

Ethylene oxide (EO) adsorption was studied on two ordered surface alloys: (2 × 2)-Sn/Pt(111) with θSn = 0.25 ML, and (√3 × √3)R30°-Sn/Pt(111) with θSn = 0.33 ML. Nearly all EO desorbs molecularly during TPD in peaks at 198 K for the (2 × 2) alloy and 190 K for the (√3 × √3)R30° alloy, corresponding to desorption activation energies of 12.1 and 11.6...

Novel LaOCl/LaCl3 catalysts have been discovered that enable the production of vinyl chloride monomer from ethane. An ethane-based process would result in both capital savings and raw materials savings when compared to the current most effective vinyl technology. These materials are unique in the world of chlorination/oxychlorination as the mechani...

Chlorinated hydrocarbons (CHCs) remain important industrial chemical intermediates and solvents, especially for the exploration of the potential of La-based materials for the conversion of chlorinated waste compounds.[1] The production of industrially important CHCs frequently occurs with concurrent formation of less desirable side-products. For ex...

The mechanism of selective production of methyl chloride by a reaction of methane, hydrogen chloride, and oxygen over lanthanum-based catalysts was studied. The results suggest that methane activation proceeds through oxidation-reduction reactions on the surface of catalysts with an irreducible metal-lanthanum, which is significantly different from...

LaCl3 is an active, selective and stable catalyst for oxidative chlorination of methane to methyl chloride. Selective conversion to methyl chloride can be achieved by limiting methane conversion, for example, by using an excess of methane in the feed. Methylene chloride and carbon monoxide are the main side products at higher methane conversion lev...

Relative activity of La2O3, LaOCl, and LaCl3 in the destructive adsorption of CCl4 to CO2 was studied with density-functional theory calculations and temperature-programmed reaction experiments monitored with IR spectroscopy. Integral absorbance of the IR peak for phosgene, which is a reaction intermediate, was obtained as a function of temperature...

The reaction mechanism of water formation from H2 and O2 was studied over a series of silica-supported gold nanoparticles. The metal particle size distributions were estimated with TEM and XRD measurements. Hydrogen and oxygen adsorption calorimetry was used to probe the nature and properties of surface species formed by these molecules. DFT calcul...

Adsorption sites of La2O3, LaOCl, and LaCl3 catalysts were characterized with probe molecules using infrared spectroscopy, temperature-programmed desorption (TPD), and density-functional theory (DFT) calculations. Surface acid sites were probed with CO, pyridine, and 2,6-dimethylpyridine (DMP), and basic sites were probed with CO2. Shifts of the CO...

Density functional theory (DFT) calculations for acetylene hydrogenation on clean, vinylidene CCH2-covered (0.25ML) and ethylidyne CCH3-covered (0.25ML) Pt(111) surfaces were performed to probe the reaction mechanism and evaluate energetic changes due to high hydrocarbon coverage. A comparison between the reaction energetics on the clean and pre-co...

The catalytic destruction of carbon tetrachloride in the presence of steam, CCl(4) + 2 H(2)O-->4 HCl + CO(2), was investigated at 200-350 degrees C over a series of lanthanide (La, Ce, Pr and Nd) and alkaline-earth metal (Mg, Ca, Sr and Ba) oxide-based catalysts with kinetic experiments, Raman spectroscopy, X-ray photoelectron spectroscopy, IR spec...

A Monte Carlo (MC) molecular model, with parameters derived from density functional theory calculations, is used to describe experimental data for the rate of ethane hydrogenolysis for a Pt/SiO2 catalyst over a wide range of conditions. The surface concentrations of the most abundant stable species (hydrogen atoms, ethylidyne species, and di-σ-bond...

A grandcanonical Monte Carlo (MC) simulation is described for calculating surface coverages of adsorbed hydrogen atoms and ethylidyne species on Pt(111) as a function of temperature and partial pressures of ethane and hydrogen. The MC simulation is based on self-consistent, gradient-corrected density functional theory (DFT) calculations of the ener...

Microcalorimetric and infrared spectroscopic studies of CO adsorption on Pt/SiO2 were conducted at temperatures from 298 to 673 K. The adsorption of CO on silica-supported Pt is equilibrated at 673 K, and the microcalorimetric and spectroscopic results obtained at this elevated temperature are in agreement with results reported for Pt(111) at 300 K...

Ethylene adsorption on a Pt/Au/SiO2 catalyst (2 wt% Pt; Au/Pt atomic ratio of 10) was studied using adsorption microcalorimetry and FTIR spectroscopy. Ethylene adsorption at 300 K on Pt/Au/SiO2 produced π‐bonded, di‐σ‐bonded, and ethylidyne species with an initial heat of 140 kJ/mol, compared to a heat of 157 kJ/mol for Pt/SiO2 on which only ethyli...

Microcalorimetric measurements were made of the interaction of hydrogen, ethene, isobutene and isobutane at 300 K with silica- supported Pt, Pd, and PtSn catalysts. The initial heats of hydrogen adsorption on silica-supported Pd and Pt are 104 and 95 kJ/mol, respectively. The presence of Sn decreases the saturation uptake of hydrogen on the PtSn sa...