Atomistic Mechanisms of Thermal Transformation in a Zr-Metal Organic Framework, MIL-140C

Swarit Dwivedi; Malgorzata Kowalik; Nilton Rosenbach; Dalal S Alqarni; Yun Kyung Shin; Yongjian Yang; John C Mauro; Akshat Tanksale; Alan L Chaffee; Adri C T van Duin

doi:10.1021/acs.jpclett.0c02930

Atomistic Mechanisms of Thermal Transformation in a Zr-Metal Organic Framework, MIL-140C

J Phys Chem Lett. 2021 Jan 14;12(1):177-184. doi: 10.1021/acs.jpclett.0c02930. Epub 2020 Dec 15.

Authors

Affiliations

¹ Department of Chemical Engineering, Monash University, Clayton 3800, Victoria, Australia.
² Department of Mechanical Engineering, The Pennsylvania State University, University Park, Pennsylvania 16802, United States.
³ Centro Universitário Estadual da Zona Oeste, Avenida Manuel Caldeira de Alvarenga 1203, 23070-200 Campo Grande, Rio de Janeiro, Brazil.
⁴ School of Chemistry, Monash University, Clayton 3800, Victoria, Australia.
⁵ Department of Materials Science and Engineering, The Pennsylvania State University, University Park, Pennsylvania 16802, United States.

PMID: 33321037
DOI: 10.1021/acs.jpclett.0c02930

Abstract

To understand the mechanisms responsible for thermal decomposition of a Zr-MOF (MIL-140C), we perform atomistic-scale molecular dynamics (MD) simulations and discuss the simulation data in comparison with the TEM images obtained for the decomposed Zr-MOF. First, we introduce the ReaxFF parameters suitable for the Zr/C/H/O chemistry and then apply them to investigate the thermal stability and morphological changes in the MIL-140C during heating. Based on the performed simulations we propose an atomic mechanism for the collapse of the MIL-140C and the molecular pathways for carbon monoxide formation, the main product of the MIL-140C thermal degradation. We also determine that the oxidation state of the ZrO_x clusters, evolved due to the thermal degradation, approximates the tetragonal phase of ZrO₂. Both simulations and experiments show a distribution of very small ZrO_x clusters embedded in the disrupted organic sheet that could contribute to the unusual high catalytic activity of the decomposed MIL-140C.