scholarly journals How covalence breaks adsorption-energy scaling relations and solvation restores them

2017 ◽  
Vol 8 (1) ◽  
pp. 124-130 ◽  
Author(s):  
Federico Calle-Vallejo ◽  
Alexander Krabbe ◽  
Juan M. García-Lastra
Keyword(s):  
Aqueous Solution ◽  
Oxygen Reduction ◽  
Adsorption Energy ◽  
Scaling Relations ◽  
Scaling Relation ◽  
Energy Scaling ◽  
Adsorption Energies

We show that under vacuum various metalloporphyrins break the scaling relation between the adsorption energies of *OH and *OOH, which can potentially boost oxygen reduction and evolution. In aqueous solution, however, such scaling relation is restored.

Adsorption energy scaling relation on bimetallic magnetic surfaces: role of surface magnetic moments

2020 ◽  
Vol 22 (32) ◽  
pp. 17960-17968
Author(s):  
Swetarekha Ram ◽  
Seung-Cheol Lee ◽  
Satadeep Bhattacharjee
Keyword(s):  
Adsorption Energy ◽  
Magnetic Moments ◽  
Linear Scaling ◽  
Scaling Relation ◽  
Energy Scaling ◽  
Magnetic Surfaces ◽  
Adsorption Energies

Linear scaling of adsorption energies in terms of surface magnetic moments.

scholarly journals Does the breaking of adsorption-energy scaling relations guarantee enhanced electrocatalysis?

2018 ◽  
Vol 8 ◽  
pp. 110-117 ◽  
Author(s):  
Nitish Govindarajan ◽  
Juan M. García-Lastra ◽  
Evert Jan Meijer ◽  
Federico Calle-Vallejo
Keyword(s):  
Adsorption Energy ◽  
Scaling Relations ◽  
Energy Scaling

Establishing and Understanding Adsorption–Energy Scaling Relations with Negative Slopes

2016 ◽  
Vol 7 (24) ◽  
pp. 5302-5306 ◽  
Author(s):  
Hai-Yan Su ◽  
Keju Sun ◽  
Wei-Qi Wang ◽  
Zhenhua Zeng ◽  
Federico Calle-Vallejo ◽  
...  
Keyword(s):  
Adsorption Energy ◽  
Scaling Relations ◽  
Energy Scaling

Departures from the Adsorption Energy Scaling Relations for Metal Carbide Catalysts

2014 ◽  
Vol 118 (24) ◽  
pp. 13026-13034 ◽  
Author(s):  
Ronald Michalsky ◽  
Yin-Jia Zhang ◽  
Andrew J. Medford ◽  
Andrew A. Peterson
Keyword(s):  
Adsorption Energy ◽  
Scaling Relations ◽  
Metal Carbide ◽  
Energy Scaling

Introducing structural sensitivity into adsorption–energy scaling relations by means of coordination numbers

2015 ◽  
Vol 7 (5) ◽  
pp. 403-410 ◽  
Author(s):  
Federico Calle-Vallejo ◽  
David Loffreda ◽  
Marc T. M. Koper ◽  
Philippe Sautet
Keyword(s):  
Adsorption Energy ◽  
Scaling Relations ◽  
Structural Sensitivity ◽  
Coordination Numbers ◽  
Energy Scaling

scholarly journals Modified Dual-Site Langmuir Adsorption Equilibrium Models from A GCMC Molecular Simulation

2020 ◽  
Vol 10 (4) ◽  
pp. 1311
Author(s):  
Junchao Wang ◽  
Yongjie Wei ◽  
Zhengfei Ma
Keyword(s):  
Molecular Simulation ◽  
Adsorption Energy ◽  
Pressure Swing Adsorption ◽  
Adsorption Equilibrium ◽  
Equilibrium Data ◽  
Different Temperatures ◽  
Adsorption Energies ◽  
Pressure Swing ◽  
Adsorption Equilibrium Data ◽  
Dual Site

In the modern industrial separation process, the pressure swing adsorption technology is widely used to separate and purify gases due to its low energy consumption, low cost, convenience, reliability, and environmental benignity. The basic elements of the design and application of the pressure swing adsorption process are adsorption isotherms at different temperatures for adsorbents. The dual-site Langmuir (DSL) adsorption equilibrium model is the mostly used model; however, this model is based on the assumption that the adsorption energy on the surface of an adsorbent is uniform and remains unchanged. Here, a grand canonical Monte Carlo (GCMC) molecular simulation was used to calculate the CO2 adsorption equilibrium on MIL-101 (Cr) at 298 K. MIL-101 (Cr) was chosen, as it has more a general pore structure with three different pores. The calculation results showed that the adsorption energies with different adsorption pressures fitted a normal distribution and the relationship of the average adsorption energies, E with pressures had a linear form described as: E = aP + c. With this relationship, the parameter b = k·exp(E/RT) in the DSL model was modified to b = k·exp((aP + c)/RT), and the modified DSL model (M-DSL) was used to correlate the adsorption equilibrium data on CO2-MIL-101 (Cr), C2H4-HHPAC, CH4-BPL, and CO2-H-Mordenite, showing better correlations than those of the DSL model. We also extended the parameter qm in the M-DSL model with the equation qm = k1 + k2T to adsorption equilibrium data for different temperatures. The obtained model (M-TDSL) was checked with the abovementioned adsorption equilibrium systems. The fitting results also indicated that the M-TDSL model could be used to improve the correlation of adsorption equilibrium data for different temperatures. The linear relationship between the average adsorption energy and adsorption pressure could be further tested in other adsorption equilibrium models to determine its universality.

Catalytic Activity of Silver Metal Supported on Doped Graphene in Alkaline Medium for Oxygen Reduction Reaction

2019 ◽  
Vol 1155 ◽  
pp. 55-69
Author(s):  
Nabila A. Karim ◽  
Nor Shahirah Shamsul ◽  
Siti Kartom Kamarudin
Keyword(s):  
Fuel Cell ◽  
Oxygen Reduction Reaction ◽  
Oxygen Reduction ◽  
Adsorption Energy ◽  
Reduction Reaction ◽  
Pt Catalyst ◽  
Nitrogen And Phosphorus ◽  
Doped Graphene ◽  
Phosphorus Doped ◽  
Silver Metal

The platinum (Pt) degradation, poisoning and carbon corrosion in acidic fuel cell has led to explore the research in alkaline fuel cell. However, the high cost of Pt has brought a lot of studies to find replacement for Pt catalyst. Due to that, silver metal is selected as non-Pt catalyst and supported by the nitrogen and phosphorus-doped on graphene for oxygen reduction reaction in alkaline medium. The adsorption energy and mechanism of the oxygen reduction reaction is studied by using density functional theory (DFT) calculation. The support catalyst of graphene is doped with three atom nitrogen and phosphorus namely as N3 and P3, respectively. The Ag supported on N3 and P3 are tested on O2, OOH, O and OH species. There are two types adsorption of O2 on N3 and P3 which is side and end-on adsorption configuration. The N3-Ag has similar adsorption energy for both configurations, but P3-Ag has low adsorption energy by end-on adsorption configuration. The effect of doped atoms on graphene also have been tested on O2, OOH, O and OH species. The result shows that increasing nitrogen doping atom has decreased the adsorption energy of O2 and vice versa on phosphorus atoms. A single phosphorus doping atom on graphene has shown the lowest adsorption energy, but the end-on configuration of P3-Ag has shown most stable adsorption. The schematic free energy profile shows that both N3-Ag and P3-Ag have high possibilities to be followed in oxygen reduction reaction mechanism but P3-Ag has advantage due to stable adsorption as non-Pt catalyst. The Ag metal supported on nitrogen and phosphorus-doped graphene show promising result to be a catalyst in alkaline fuel cell.

scholarly journals Volume-area scaling for debris-covered glaciers

2020 ◽  
Vol 66 (259) ◽  
pp. 880-886
Author(s):  
Argha Banerjee
Keyword(s):  
Global Scale ◽  
Scaling Relations ◽  
Scaling Exponent ◽  
Scaling Relation ◽  
Model Simulations ◽  
Ice Volume ◽  
Himalayan Glaciers ◽  
Glacier Changes ◽  
Best Fit ◽  
The Himalaya

AbstractA volume-area scaling relation is commonly used to estimate glacier volume or its future changes on a global scale. The presence of an insulating supraglacial debris cover alters the mass-balance profile of a glacier, potentially modifying the scaling relation. Here, the nature of scaling relations for extensively debris-covered glaciers is investigated. Theoretical arguments suggest that the volume-area scaling exponent for these glaciers is ~7% smaller than that for clean glaciers. This is consistent with the results from flowline-model simulations of idealised glaciers, and the available data from the Himalaya. The best-fit scale factor for debris-covered Himalayan glaciers is ~60% larger compared to that for the clean ones, implying a significantly larger stored ice volume in a debris-covered glacier compared to a clean one having the same area. These results may help improve scaling-based estimates of glacier volume and future glacier changes in regions where debris-covered glaciers are abundant.

Sign in / Sign up

Export Citation Format

Share Document