Cu- and Zr-based metal organic frameworks and their composites with graphene oxide for capture of acid gases at ambient temperature
- Department of Chemical Engineering, The Petroleum Institute, Khalifa University of Science&Technology, P.O. Box 2533, Abu Dhabi (United Arab Emirates)
- Institute of Nanoscience and Nanotechnology (INN), Demokritos National Research Center, Athens 153 10 (Greece)
- School of Chemical Engineering, National Technical University of Athens, Athens 157 80 (Greece)
Highlights: • Incorporation of GO in Cu- and Zr-based MOFs resulted in additional porosity at the interstitial MOF/GO spaces. • The UiO-66-NH{sub 2}/GO composite exhibited enhanced CO{sub 2} capacity at higher pressures. • CO{sub 2}/N{sub 2} selectivity of HKUST-1/GO was higher compared to pure HKUST-1. • The HKUST-1 crystallites in the presence of GO exhibited enhanced H{sub 2}S sorption kinetics. • The UiO-66 based adsorbents were more stable in humidity conditions than the HKUST-1 based ones. - Abstract: Capture of acid gases (CO{sub 2} and H{sub 2}S) by liquid solvent absorption is the common industrial practice, yet capture relying on solid adsorbents is increasingly gaining interest as potential alternative towards less energy-demanding operations. Herein, we developed and examined various metal organic frameworks (MOFs) bearing Cu- and Zr- metal clusters and their composites with graphene oxide (GO), and evaluated their performance for CO{sub 2} and H{sub 2}S adsorption. Specifically, UiO-66, UiO-66-NH{sub 2}, HKUST-1, and their GO composites were grown, subjected to structural, morphological, and textural characterization, and subsequently evaluated for their adsorption capacity and selectivity at ambient temperature. The crystallinity of the parent MOFs was preserved upon in-situ growth of the MOF/GO composites, while incorporation of GO yielded uniformly-shaped and well-dispersed MOF crystals resulting in enhanced sorption kinetics, and increased the pore volume compared to pure MOFs due to additional porosity formed in the interstitial spaces between the MOF crystallites and the GO flakes. To this extent, the interplay between additional porosity and pore functionalities in the competitive CO{sub 2} and N{sub 2} adsorption was investigated. UiO-66-NH{sub 2} exhibited enhanced CO{sub 2} capacity (3.07 mmol/g at 25 °C and 4 bar) and the highest CO{sub 2}/N{sub 2} selectivity (167 at 1 bar) among the tested MOFs, due to the presence of the amine functional groups in the organic linker that enhanced affinity with CO{sub 2}. At increased pressures, the UiO-66-NH{sub 2}/GO composite exhibited higher CO{sub 2} capacity compared to pure UiO-66-NH{sub 2}, which is attributed to activation of the additional porosity between the MOF crystallites and the GO layers. HKUST-1/GO selectivity was also enhanced compared to HKUST-1 in all pressures tested. Under humid environment, the UiO-66 based structures were relatively stable in contrast to the HKUST-1 ones that underwent gradual degradation. These composites offer functionalization tunability due to the presence of both MOF and GO counterparts for targeted gas capture applications.
- OSTI ID:
- 22890243
- Journal Information:
- Journal of Solid State Chemistry (Print), Journal Name: Journal of Solid State Chemistry (Print) Vol. 266; ISSN 0022-4596; ISSN JSSCBI
- Country of Publication:
- Netherlands
- Language:
- English