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Title: Olefin Adsorption on Silica-Supported Silver Salts - A DFT Study

Abstract

Recent experiments have shown that silver salts supported on mesoporous silicas display excellent adsorption selectivities of ethylene over ethane and propylene over propane. Employing the techniques of density functional theory, we have investigated the fundamental bases of this separation process by examining silver salts dispersed on model silica surfaces. Our model system includes Ag+ cations, their counteranions, silica supports, and surface silanols. Both adsorption geometries and energetics of ethylene and propylene were explored. Our results indicate that the nature of the Ag-olefin interaction is predominantly hybridization between Ag d and olefin states, which is supported by analyses of electron density difference plots and density of states. The counteranions, such as NO3 -, were found to interact strongly with surface silanols through multiple hydrogen bonds but have limited effect on the adsorption energy of olefins on the Ag+ cations. The current work supports recent experiments, which indicate that Ag-salt/silica may be a very promising adsorbent for olefin/paraffin separation.

Authors:
 [1];  [1];  [1]
  1. ORNL
Publication Date:
Research Org.:
Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States). Center for Computational Sciences
Sponsoring Org.:
USDOE Office of Science (SC)
OSTI Identifier:
930796
DOE Contract Number:
AC05-00OR22725
Resource Type:
Journal Article
Resource Relation:
Journal Name: Langmuir; Journal Volume: 22; Journal Issue: 13
Country of Publication:
United States
Language:
English

Citation Formats

Sumpter, Bobby G, Dai, Sheng, and Jiang, Deen. Olefin Adsorption on Silica-Supported Silver Salts - A DFT Study. United States: N. p., 2006. Web.
Sumpter, Bobby G, Dai, Sheng, & Jiang, Deen. Olefin Adsorption on Silica-Supported Silver Salts - A DFT Study. United States.
Sumpter, Bobby G, Dai, Sheng, and Jiang, Deen. Sun . "Olefin Adsorption on Silica-Supported Silver Salts - A DFT Study". United States. doi:.
@article{osti_930796,
title = {Olefin Adsorption on Silica-Supported Silver Salts - A DFT Study},
author = {Sumpter, Bobby G and Dai, Sheng and Jiang, Deen},
abstractNote = {Recent experiments have shown that silver salts supported on mesoporous silicas display excellent adsorption selectivities of ethylene over ethane and propylene over propane. Employing the techniques of density functional theory, we have investigated the fundamental bases of this separation process by examining silver salts dispersed on model silica surfaces. Our model system includes Ag+ cations, their counteranions, silica supports, and surface silanols. Both adsorption geometries and energetics of ethylene and propylene were explored. Our results indicate that the nature of the Ag-olefin interaction is predominantly hybridization between Ag d and olefin states, which is supported by analyses of electron density difference plots and density of states. The counteranions, such as NO3 -, were found to interact strongly with surface silanols through multiple hydrogen bonds but have limited effect on the adsorption energy of olefins on the Ag+ cations. The current work supports recent experiments, which indicate that Ag-salt/silica may be a very promising adsorbent for olefin/paraffin separation.},
doi = {},
journal = {Langmuir},
number = 13,
volume = 22,
place = {United States},
year = {Sun Jan 01 00:00:00 EST 2006},
month = {Sun Jan 01 00:00:00 EST 2006}
}