Enhancement effect of lithium-doping functionalization on methanol adsorption in copper-based metal-organic framework. (17th February 2015)

• Record Type: Journal Article
• Authors: Wu, Ying; Liu, Defei; Chen, Huiyong; Qian, Yu; Xi, Hongxia; Xia, Qibin
• Is Part Of: Chemical engineering science. Volume 123(2015)
• Page Start: 1
• Page End: 10
• Publication Date: 2015-02-17
• Subjects: Adsorption -- Li-doping functionalization -- Cu-BTC -- Methanol -- GCMC -- DFT; Chemical engineering -- Periodicals; Génie chimique -- Périodiques; Chemical engineering; Periodicals; Electronic journals; 660
• DOI: 10.1016/j.ces.2014.10.010
• Languages: English
• ISSNs: 0009-2509

Abstract

Abstract: Grand canonical Monte Carlo (GCMC) simulations combined with density functional theory (DFT) calculations were performed to evaluate the functionality effect of Li-doping on methanol adsorption over copper-based metal–organic frameworks (MOFs). In this work, a new Li-doping structure, Cu-BTC-Li, was theoretically constructed by introducing Li above both sides of organic linkers in Cu-BTC. Compared to the original Cu-BTC, Cu-BTC-Li shows higher methanol capacity and more continuous adsorption behavior in the measured pressure range. It can be attributed to the new adsorption sites (Li-sites) created by Li atoms, which turn to be the first preferential adsorption sites instead of Cu-sites, as revealed by the more exothermic binding energies (BEs) on Li-site (−90.55 kJ/mol) than the latter (−45.14 kJ/mol). Li-doping also shows varied effects on methanol adsorption at different pressures. The electrostatic interaction between methanol and framework plays a predominant role (with contribution over 95%) in the adsorption at low pressures, and Li-doping enhances adsorption by increasing the electrostatic potential of the framework. Although the dispersive interactions govern the adsorption at high pressures, Li-doping contributes to the dispersion. The present Li-doped functionalization can be extended to design new MOFs with high performance of alcohol capture in the future. Graphical abstract: Highlights: Cu-BTC-Li has been theoretically constructed by ligand functionality of Cu-BTC. Li-doping effect on methanol adsorption over Cu-BTC is studied by GCMC-DFT method. Cu-BTC-Li shows higher capacity and more continuous sorption behavior than Cu-BTC. Electrostatic or dispersive interaction governs the adsorption at varied pressures. Li-doping improves adsorption by increasing electropositivity and dispersion.