Enhancing effect of UV activation of graphene oxide on carbon capture performance of metal-organic framework / graphene oxide hybrid adsorbents

An In-Situ-Grown Cu-BTC Metal–Organic Framework / Graphene Oxide Hybrid Adsorbent for Selective Hydrogen Storage at Ambient Temperature

“…Evidently, the intensity of the peaks in the hybrid structure is enhanced compared to the parent MOF, which is attributed to the in situ growth and the contributing role of the GO support, as also shown in our previous work for analogous support-originated MOF growth. 49 In both patterns, the characteristic reflections peaks of the (200), ( 220), ( 222), (400), (331), (420), ( 422), (500), ( 440), (600), (620), ( 444), ( 551), ( 731), ( 822), ( 751), (773), and (882) crystal planes of Cu-BTC located at 6.84°, 9.64°, 11.77°, 13.59°, 14.82°, 15.18°, 16.64°, 17.61°, 19.19°, 20.35°, 21.44°, 23.51°, 24.24°, 26.07°, 28.87°, 29.48°, 35.38°, and 39.27°, respectively, are evident, yet significantly intensified in the case of the Cu-BTC/GO hybrid, 14,21 signifying the increased rigidity/crystallinity of the Cu-BTC/ GO hybrid, compared to the parent Cu-BTC crystals. The XRD pattern of the bare GO is shown as an inset in Figure 1.…”

“…The remnant mass at 600 °C is ∼33%, containing solid decomposition products, i.e., metallic Cu, Cu oxides, and carbon. 21 The TGA profile of GO shows three main weight loss steps: a first one up to ∼100 °C, which is due to the removal of adsorbed water; one in the 200−250 °C range, which is attributed to the surface labile oxygen groups, 52 accounting for ∼27% of the weight loss; and a transition in the 440−480 °C range, which is due to the structure degradation particularly related to sp 3 carbon atoms located at the defect centers, as well as to the removal of firm oxygen groups. 53 The remnant amount of GO at the terminal temperature of 600 °C is 45%.…”

“…The formed structure includes equatorial as well as axial coordinations of oxygen groups on the GO surfaces with Cu ions, on account of the octahedral morphology of Cu complexes. 14,21 The basis of equatorial coordination is the substitution of a benzenetricarboxylate with a carboxylic-type surface group, while axial coordination involves hydroxylic or epoxy group-mediated interaction and resultant switching of a water molecule. 14,54 The added multimode porosity for the MOF/GO hybrid, which was identified by liquid N 2 adsorption, as discussed above, can be explained by the disordered structure that results from differences in the interactions and coordination with carboxylic groups at the edges, and hydroxylic or epoxy ones on the basal planes of the graphitic layers.…”

“…14,21,22 Cu-BTC exhibits abundancy of active Cu sites and is formed by a 3-D assembly of Cu dimers of the Cu clusters and oxygen atoms of the benzene-1,3,5-tricarboxylic acid linker in Fm3̅ m symmetry, which results in the formation of face-centered-cubic lattices as Cu 2 (COO) 4 -paddle wheels. 14,21,23,24 Cu-BTC has been synthesized by a variety of techniques including ambient temperature stirring, hydrothermal, solvothermal, microwaveassisted, sonochemical, mechanochemical, and electrochemical methods, involving various precursors and precursor modifications, varying reaction temperature, time, and medium, drying conditions, and activation protocols, while it has been modified/functionalized by incorporation of various other material counterparts (hybrids) and molecular species. 14,21,24,25 Rosi et al 26 investigated, for the first time, the potentiality of MOFs for hydrogen storage in 2003.…”

“…14,21,23,24 Cu-BTC has been synthesized by a variety of techniques including ambient temperature stirring, hydrothermal, solvothermal, microwaveassisted, sonochemical, mechanochemical, and electrochemical methods, involving various precursors and precursor modifications, varying reaction temperature, time, and medium, drying conditions, and activation protocols, while it has been modified/functionalized by incorporation of various other material counterparts (hybrids) and molecular species. 14,21,24,25 Rosi et al 26 investigated, for the first time, the potentiality of MOFs for hydrogen storage in 2003. In this work, a hydrogen uptake of 0.25 wt % was obtained for MOF-5 (Zn 4 O(BDC) 3 ) at 298 K and 5 bar.…”