Structural and CO2 Capture Properties of Ethylenediamine-Modified HKUST-1 Metal–Organic Framework

Nika Vrtovec,Matjaž Mazaj,Janez Kovač,Gianpiero Buscarino,Angela Terracina,Iztok Arčon,Nataša Zabukovec Logar,Simonpietro Agnello

doi:10.1021/acs.cgd.0c00667

Abstract

The high structural and compositional flexibility of metal–organic frameworks (MOFs) shows their great potential for CO2 capture and utilization in accordance with the environmental guidelines of low-carbon technology developments. HKUST-1 as one of the most intensively studied representatives of MOFs for such purposes excels because of its simplicity of production and high ability to tune its intrinsic properties by various functionalization processes. In the present work, ethylenediamine functionalization was performed for the first time in order to thoroughly investigate the amine sorption sites’ impact on the CO2 capture performance of HKUST-1. The placement of ethylenediamine moieties on Cu2+ free-metal sites has been examined in detail and confirmed by using various spectroscopic techniques such as Fourier transform infrared spectroscopy, electron paramagnetic resonance, Raman, and Cu K-edge extended X-ray absorption fine structure/X-ray absorption near edge structure. N2 and CO2 sorption tests have proven that the functionalization reduces both the specific surface area and the CO2 sorption capacity, but on the other hand, it increases the binding energy by 85% (from −20.3 kJ/mol to −36.8 kJ/mol) and CO2/N2 selectivity at 0.15/0.85 bar by 100% and notably improves the kinetics of adsorption in comparison to the pristine HKUST-1 material.

Highlights

Postcombustion CO2 capture (PCC) is a well-established method of carbon capture and storage (CCS) technology enabling retrofitting at a point source and sustainability of the combustion process
The conventional PCC process based on chemisorption in monoethanolamine solutions suffers drawbacks of a large energy penalty for sorbent regeneration, thermal and oxidative amine degradation, and corrosion issues.[1−9] the alternative technology based on physisorption on solid sorbents, which to a major extent surpasses the abovementioned drawbacks, has been intensively studied
Several materials have been developed for CO2 capture, based on physisorption on solid adsorbents, e.g., porous organic polymers, covalent organic framework, activated carbon, zeolites, and metal−organic framework (MOFs).[3,5,14]

Summary

Introduction

Postcombustion CO2 capture (PCC) is a well-established method of carbon capture and storage (CCS) technology enabling retrofitting at a point source and sustainability of the combustion process. Cu K-edge EXAFS analysis is used to probe the average local structure around Cu cations in the activated HKUST-1 and all functionalized materials.

Results

Conclusion