Hydrogenation of Carbon Dioxide to Formate by Noble Metal Catalysts Supported on a Chemically Stable Lanthanum Rod-Metal-Organic Framework

Maureen Gumbo; Banothile C E Makhubela; Francoise M Amombo Noa; Lars Öhrström; Bassem Al-Maythalony; Gift Mehlana

doi:10.1021/acs.inorgchem.3c00884

Hydrogenation of Carbon Dioxide to Formate by Noble Metal Catalysts Supported on a Chemically Stable Lanthanum Rod-Metal-Organic Framework

Inorg Chem. 2023 Jun 12;62(23):9077-9088. doi: 10.1021/acs.inorgchem.3c00884. Epub 2023 May 31.

Authors

Maureen Gumbo^{1

2}, Banothile C E Makhubela², Francoise M Amombo Noa³, Lars Öhrström³, Bassem Al-Maythalony⁴, Gift Mehlana¹

Affiliations

¹ Department of Chemical Sciences, Faculty of Science and Technology, Midlands State University, Private Bag 9055, Senga Road, Gweru 263, Zimbabwe.
² Research Centre for Synthesis and Catalysis, Department of Chemical Sciences, Faculty of Science, University of Johannesburg, Kingsway Campus: C2 Lab 328, Auckland Park, Johannesburg 2006, South Africa.
³ Department of Chemistry and Chemical Engineering, Chalmers University of Technology, SE-412 96 Göteborg, Sweden.
⁴ Materials Discovery Research Unit, Advanced Research Centre, Royal Scientific Society, Amman 11941, Jordan.

PMID: 37256920
DOI: 10.1021/acs.inorgchem.3c00884

Abstract

The conversion of carbon dioxide to formate is of great importance for hydrogen storage as well as being a step to access an array of olefins. Herein, we have prepared a JMS-5 metal-organic framework (MOF) using a bipyridyl dicarboxylate linker, with the molecular formula [La₂(bpdc)_3/2(dmf)₂(OAc)₃]·dmf. The MOF was functionalized by cyclometalation using Pd(II), Pt(II), Ru(II), Rh(III), and Ir(III) complexes. All metal catalysts supported on JMS-5 showed activity for CO₂ hydrogenation to formate, with Rh(III)@JMS-5a and Ir(III)@JMS-5a yielding 4319 and 5473 TON, respectively. X-ray photoelectron spectroscopy of the most active catalyst Ir(III)@JMS-5a revealed that the iridium binding energies shifted to lower values, consistent with formation of Ir-H active species during catalysis. The transmission electron microscopy images of the recovered catalysts of Ir(III)@JMS-5a and Rh(III)@JMS-5a did not show any nanoparticles. This suggests that the catalytic activity observed was due to Ir(III) and Rh(III). The high activity displayed by Ir(III)@JMS-5a and Rh(III)@JMS-5a compared to using the Ir(III) and Rh(III) complexes on their own is attributed to the stabilization of the Ir(III) and Rh(III) on the nitrogen and carbon atom of the MOF backbone.