Programme

P.58 -- Poster, VCTP-47

Date: Thursday, 4 August 2022

Time: 08:30 - 10:00

H2 physisorption on the internal surface of metal organic framework MOF-74 based materials by ab initio molecular dynamics simulation

Trang Thuy Nguyen(a,b), Phong Hoang Le(a), Nam Hoang Vu(c,d), Linh Nguyen Hoang(e), Toan The Nguyen(a), Thang Bach Phan(b,d) and Duc Nguyen-Manh(f)

(a) Key Laboratory for Multiscale Simulation of Complex Systems, University of Science, Vietnam National University – Hanoi, Hanoi, Vietnam; (b) Center for Innovative Materials and Architectures, Vietnam National University Ho Chi Minh City, Ho Chi Minh City, Vietnam; (c) Faculty of Materials Science and Technology, University of Science, Ho Chi Minh City, Vietnam; (d) Vietnam National University, HoChiMinh City, Vietnam; (e) School of Engineering Physics, Hanoi University of Science and Technology, 1 Dai Co Viet road, Hanoi, Vietnam; (f) CCFE, United Kingdom Atomic Energy Authority, Abingdon, OX14 3DB, UK.

MOF-74 is one of the best H2 physisorptive metal organic frameworks owing to the occurrence of unsaturated metal sites, called open metal sites, which induces strong electrostatic H2 attraction. However, the host – guest binding strength is still needed to be further enhanced for efficient hydrogen storage at ambient conditions. In this work, MOF-74 was modified in various ways including linker functionalization, linker substitution, open metal site fluorination. The H2 adsorption positions on the internal surface of the materials were investigated by ab initio molecular dynamics simulations. The electronic structures were examined to demonstrate the host-guest binding mechanisms. It was shown that using shorter non-aromatic linker can increase the density of strong adsorption sites but the binding strength is slightly reduces by 1.5 kJ/mol due to the absence of aromatic ring. Functionalizing the aromatic linker with -OH, -F, -NH3 functional groups reduces the aromaticity of the ring so that the H2 affinity of the framework reduces. The fluorine atom capping at open metal site shows remarkable H2 adsorption performance. It can adsorb 4 H2 molecules with binding strength larger than all non-open-metal sites in the original framework by ~ 4 kJ/mol.

Presenter: Nguyen Thuy Trang