On the HKUST-1/GO and HKUST-1/rGO Composites: The Impact of Synthesis Method on Physicochemical Properties

Abstract

The chemical stability and adsorptive/catalytic properties of the most widely studied metal–organic framework (MOF), which is HKUST-1, can be improved by its combination with graphene oxide (GO) or reduced graphene oxide (rGO). The chemistry of GO or rGO surfaces has a significant impact on their interaction with MOFs. In this work, we demonstrate that GO and rGO interaction with HKUST-1 influences the morphology and textural properties but has no impact on the thermal stability of the final composites. We also show that synthesis environment, e.g., stirring, to some extent influences the formation of HKUST-1/GO and HKUST-1/rGO composites. Homogeneous samples of the sandwich-type composite can be obtained when using reduced graphene oxide decorated with copper (Cu/rGO), which, owing to the presence of Cu sites, allows the direct crystallisation of HKUST-1 and its further growth on the graphene surface. This work is the first part of our research on HKUST-1/GO and HKUST-1/rGO and deals with the influence of the type of graphene material and synthesis parameters on the composites’ physicochemical properties that were determined by using X-ray diffraction, scanning and transmission electron microscopy, Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, and thermogravimetric analysis.

HKUST-1/ZIF-67 Nanocomposites as Heterogeneous Cu–Co-Bimetallic Fenton-like Catalysts for Efficient Removal of Methylene Blue

“…The N 2 adsorption–desorption isotherms and pore size distribution of ZIF-67, HKUST-1, and HKUST-1/ZIF-67-7% are shown in Figure S4, and the key pore parameters are listed in Table S1. It can be seen that both ZIF-67, HKUST-1 and HKUST-1/ZIF-67- X presented type-IV isotherm with an obvious hysteresis loop, indicating the presence of mesopores in these materials. These were consistent with the results of pore size distribution.…”

“…The peaks at 729 cm −1 could be assigned to the stretching vibration of Cu−O. 37 In ZIF-67, the characteristic peaks at 600−1500 cm −1 belonged to the planar and tensile vibrations of the imidazole ring. 38 A significant band at 1580 cm −1 was observed, attributable to the stretching vibration of C�N.…”

“…In HKUST-1, the peaks at 1449 and 1374 cm –1 were observed which could be attributed to the CO stretching and C–O bending vibrations in the H 3 BTC ligand, respectively. The peaks at 729 cm –1 could be assigned to the stretching vibration of Cu–O . In ZIF-67, the characteristic peaks at 600–1500 cm –1 belonged to the planar and tensile vibrations of the imidazole ring .…”

Enhanced Gas Adsorption in HKUST-1@Chitosan Aerogels, Cryogels, and Xerogels: An Evaluation Study

“…Additionally, a new band at 1371 cm −1 , derived from C�C stretching in the aromatic ring of the linker, is observed. 26 Furthermore, the NH 2 band is shifted toward lower wavenumbers in the spectrum of HKUST-1@CS beads (1554 cm −1 for HKUST-1@CS 1:2 C, 1560 cm −1 for HKUST-1@CS 1:1 C, and 1550 cm −1 for HKUST-1@CS 2:1 C), indicating electron density donation from NH 2 to the copper center (NH 2 → Cu). Finally, the visible bands at 454−477 cm −1 are characteristic of the Cu−N stretching band.…”

“…Specifically, the absorption band at 727 cm –1 is attributed to Cu–O stretching, resulting from either metal–organic coordination in MOFs or chelating bonds between the metal and hydroxyl groups of chitosan. Additionally, a new band at 1371 cm –1 , derived from CC stretching in the aromatic ring of the linker, is observed . Furthermore, the NH 2 band is shifted toward lower wavenumbers in the spectrum of HKUST-1@CS beads (1554 cm –1 for HKUST-1@CS 1:2 C , 1560 cm –1 for HKUST-1@CS 1:1 C , and 1550 cm –1 for HKUST-1@CS 2:1 C ), indicating electron density donation from NH 2 to the copper center (NH 2 → Cu).…”