scholarly journals A Simple Bond-Additivity Model Explains Large Decreases in Heats of Adsorption in Solvents Versus Gas Phase: A Case Study with Phenol on Pt(111) in Water

ACS Catalysis ◽  
2019 ◽  
Vol 9 (9) ◽  
pp. 8116-8127 ◽  
Author(s):  
Nirala Singh ◽  
Charles T. Campbell
Keyword(s):  
Gas Phase ◽  
Heats Of Adsorption

Modeling Solar Thermochemical Splitting of CO2 Using Metal Oxide and a CR5

2010 ◽  
Author(s):  
Ken S. Chen ◽  
Roy E. Hogan
Keyword(s):  
Gas Phase ◽  
The Finite Element Method ◽  
Species Concentration ◽  
Neutral Gas ◽  
Solar Thermochemical ◽  
Multiple Species ◽  
Carbon Dioxide Co2 ◽  
Product Species ◽  
Account Heat

A two-dimensional, multi-physics computational model based on the finite-element method is developed for simulating the process of solar thermochemical splitting of carbon dioxide (CO2) using ferrites (Fe3O4/FeO) and a counter-rotating-ring receiver/recuperator or CR5, in which carbon monoxide (CO) is produced from gaseous CO2. The model takes into account heat transfer, gas-phase flow and multiple-species diffusion in open channels and through pores of the porous reactant layer, and redox chemical reactions at the gas/solid interfaces. Results (temperature distribution, velocity field, and species concentration contours) computed using the model in a case study are presented to illustrate model utility. The model is then employed to examine the effects of injection rates of CO2 and argon neutral gas, respectively, on CO production rate and the extent of the product-species crossover.

scholarly journals Development of an atmospheric chemistry model coupled to the PALM model system 6.0: Implementation and first applications

2020 ◽  
Author(s):  
Basit Khan ◽  
Sabine Banzhaf ◽  
Edward C. Chan ◽  
Renate Forkel ◽  
Farah Kanani-Sühring ◽  
...  
Keyword(s):  
Urban Environment ◽  
Gas Phase ◽  
Atmospheric Chemistry ◽  
Horizontal Resolution ◽  
Model System ◽  
Gas Phase Chemistry ◽  
Photostationary State ◽  
Emission Mode ◽  
Phase Chemistry

Abstract. In this article we describe the implementation of an online-coupled gas-phase chemistry model in the turbulence resolving PALM model system 6.0. The new chemistry model is part of the PALM-4U components (read: PALM for you; PALM for urban applications) which are designed for application of PALM model in the urban environment (Maronga et al., 2020). The latest version of the Kinetic PreProcessor (KPP, 2.2.3), has been utilised for the numerical integration of gas-phase chemical reactions. A number of tropospheric gas-phase chemistry mechanisms of different complexity have been implemented ranging from the photostationary state to more complex mechanisms such as CBM4, which includes major pollutants namely O3, NO, NO2, CO, a simplified VOC chemistry and a small number of products. Further mechanisms can also be easily added by the user. In this work, we provide a detailed description of the chemistry model, its structure along with its various features, input requirements, its application and limitations. A case study is presented to demonstrate the application of the new chemistry model in the urban environment. The computation domain of the case study is comprised of part of Berlin, Germany, covering an area of 6.71 × 6.71 km with a horizontal resolution of 10 m. We used "PARAMETERIZED" emission mode of the chemistry model that only considers emissions from traffic sources. Three chemical mechanisms of varying complexity and one no-reaction (passive) case have been applied and results are compared with observations from two permanent air quality stations in Berlin that fall within the computation domain. The results show importance of online photochemistry and dispersion of air pollutants in the urban boundary layer. The simulated NOx and O3 species show reasonable agreement with observations. The agreement is better during midday and poorest during the evening transition hours and at night. CBM4 and SMOG mechanisms show better agreement with observations than the steady state PHSTAT mechanism.

scholarly journals Are TiO2-based exterior paints useful catalysts for gas-phase photooxidation processes? A case study on n-decane abatement for air detoxification

2014 ◽  
Vol 147 ◽  
pp. 988-999 ◽  
Author(s):  
Ricardo A.R. Monteiro ◽  
Filipe V.S. Lopes ◽  
Adrián M.T. Silva ◽  
Joana Ângelo ◽  
Gabriela V. Silva ◽  
...  
Keyword(s):  
Gas Phase

Patterns of diamond nucleation from the gas phase

1993 ◽  
Vol 8 (4) ◽  
pp. 798-810 ◽  
Author(s):  
E. Molinari ◽  
R. Polini ◽  
M. Tomellini
Keyword(s):  
Gas Phase ◽  
Total Pressure ◽  
Active Sites ◽  
Preceding Paper ◽  
Kinetic Scheme ◽  
Necessary Condition ◽  
Molecular Models ◽  
Gaseous Species ◽  
Diamond Nucleation ◽  
Heats Of Adsorption

On the basis of an analysis of experimental data on nucleation rates performed in the preceding paper in this issue, patterns of the process of diamond nucleation from the gas phase on Si(100) substrates have been drawn. A kinetic scheme is proposed which is apparently able to describe the complex behavior of the system in the temperature range 750 K−1225 K, at (CH4/H2) ratios between 0.5 and 2% and at a total pressure of 100 mbar. The model postulates a distribution function of the nucleation centers over the heats of adsorption of active gaseous species and introduces a cut-off criterion based on the necessary condition that adjacent active sites coexist for times longer than the characteristic time of germ growth. Nucleation centers, active sites, germs, and nuclei have been defined by simple molecular models and their rates of transformation discussed, using available literature data.

Heat of adsorption of oxygen on uranium dioxide at ‒183° C

1957 ◽  
Vol 241 (1224) ◽  
pp. 67-79 ◽  
Keyword(s):  
Gas Phase ◽  
Uranium Dioxide ◽  
Physical State ◽  
Heat Of Adsorption ◽  
Slow Process ◽  
Kcal Mole ◽  
Heats Of Adsorption ◽  
Isothermal Calorimeter ◽  
Incremental Addition ◽  
Initial Heat

A number of specimens of uranium dioxide have been prepared and studied in a non-adiabatic non-isothermal calorimeter at ‒183° C. Uptake of oxygen by the oxide is rapid. Incremental addition of oxygen has yielded differential heats of adsorption which decrease on all specimens as the surface becomes covered. The initial heat of adsorption is 55 ± 2 kcal/mole. The rate of evolution of heat becomes increasingly slow for successive increments of oxygen adsorbed. This slow process takes place after the disappearance of all the oxygen from the gas phase and must therefore be a reaction in or on the oxide. It is discussed in terms of a slow change to the chemisorbed state of oxygen molecules rapidly adsorbed initially in the physical state.

Conformational changes in hydroxyl functional group upon hydration: the case study of Endo Fenchol

2020 ◽  
Author(s):  
Elias M Neeman ◽  
Thérèse Huet
Keyword(s):  
Fourier Transform ◽  
Gas Phase ◽  
Conformational Changes ◽  
Functional Group ◽  
Theoretical Calculations ◽  
Supersonic Jet ◽  
Microwave Spectrometer ◽  
Supersonic Jet Expansion ◽  
Hydroxyl Functional Group

The hydration of endo-fenchol has been studied in the gas phase using a combination of Fourier transform microwave spectrometer coupled to a supersonic jet expansion and theoretical calculations in the...

Tautomerism and mechanism of intramolecular proton transfer under the gas phase and micro-hydrated solvent conditions: biuret as a case study

2014 ◽  
Vol 26 (1) ◽  
pp. 159-169 ◽  
Author(s):  
Abdol Reza Hajipour ◽  
Alireza Najafi Chermahini ◽  
Morteza Karimzadeh ◽  
Mehdi Rezapour
Keyword(s):  
Proton Transfer ◽  
Gas Phase ◽  
Intramolecular Proton Transfer
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