Issue 28, 2022

Pyrolysis of a metal–organic framework followed by in situ X-ray absorption spectroscopy, powder diffraction and pair distribution function analysis

Abstract

Metal–organic frameworks (MOFs) can serve as precursors for new nanomaterials via thermal decomposition. Such MOF-derived nanomaterials (MDNs) are often comprised of metal and/or metal oxide particles embedded on porous carbon. The morphology of MDNs is similar to that of the precursor MOF, and improved stability and catalytic properties have been demonstrated. However, the pathway from MOF to MDN is only well understood for a few systems, and in situ studies are needed to elucidate the full phase behaviour and time/temperature dependency. In this work, we follow the MOF-to-MDN transformation in situ by using three complementary techniques: X-ray absorption spectroscopy (XAS), powder X-ray diffraction (PXRD), and X-ray total scattering/pair distribution function (TS/PDF) analysis. The thermal decomposition of HKUST-1, i.e. the archetypical MOF Cu3(btc = 1,3,5-benzenetricarboxylate)2, is followed from room temperature to 500 °C by applying different heating ramps. Real space correlations are followed by PDF and extended X-ray absorption fine structure (EXAFS) analysis, and quantitative phase fractions are obtained by refinement of PXRD and PDF data, and by linear combination analysis (LCA) of X-ray absorption near edge Structure (XANES) data. We find that HKUST-1 decomposes at 300–325 °C into copper(I) oxide and metallic copper. Above 350–470 °C, metal particles remain as the only copper species. There is an overall good agreement between all three techniques with respect to the phase evolution, and the study paves the road towards rational synthesis of a Cu2O/Cu/carbon material with the desired metal/metal oxide composition. More importantly, our investigations serve as a benchmark study demonstrating that this methodology is generally applicable for studying the thermal decomposition of MOFs.

Graphical abstract: Pyrolysis of a metal–organic framework followed by in situ X-ray absorption spectroscopy, powder diffraction and pair distribution function analysis

Supplementary files

Article information

Article type
Paper
Submitted
25 Kol 2022
Accepted
20 Mme 2022
First published
21 Mme 2022

Dalton Trans., 2022,51, 10740-10750

Pyrolysis of a metal–organic framework followed by in situ X-ray absorption spectroscopy, powder diffraction and pair distribution function analysis

M. Folkjær, L. F. Lundegaard, H. S. Jeppesen, M. J. Marks, M. S. Hvid, S. Frank, G. Cibin and N. Lock, Dalton Trans., 2022, 51, 10740 DOI: 10.1039/D2DT00616B

To request permission to reproduce material from this article, please go to the Copyright Clearance Center request page.

If you are an author contributing to an RSC publication, you do not need to request permission provided correct acknowledgement is given.

If you are the author of this article, you do not need to request permission to reproduce figures and diagrams provided correct acknowledgement is given. If you want to reproduce the whole article in a third-party publication (excluding your thesis/dissertation for which permission is not required) please go to the Copyright Clearance Center request page.

Read more about how to correctly acknowledge RSC content.

Social activity

Spotlight

Advertisements