Graphene Oxide Facilitates Transformation of Waste PET into MOF Nanorods in Ionic Liquids

Abstract

Although though ionic liquids (IL) are rapidly emerging as highly efficient reagents for the depolymerization of waste plastics, their high cost and adverse impact on the environment make the overall process not only expensive but also environmentally harmful. In this manuscript, we report that graphene oxide (GO) facilitates the transformation of waste polyethylene terephthalate (PET) to Ni-MOF (metal organic framework) nanorods anchored on reduced graphene oxide (Ni–MOF@rGO) through NMP (N-Methyl-2-pyrrolidone)-based coordination in ionic liquids. Morphological studies using scanning electron microscopy (SEM) and transmission electron microscopy (TEM) showed mesoporous three-dimensional structures of micrometer-long Ni-MOF nanorods anchored on reduced graphene substrates (Ni–MOF@rGO ), whereas structural studies using XRD and Raman spectra demonstrated the crystallinity of Ni-MOF nanorods. Chemical analysis of Ni–MOF@rGO carried out using X-ray photoelectron spectroscopy demonstrated that nickel moieties exist in an electroactive OH-Ni-OH state, which was further confirmed by nanoscale elemental maps recorded using energy-dispersive X-ray spectroscopy (EDS). The applicability of Ni–MOF@rGO as an electro-catalyst in a urea-enhanced water oxidation reaction (UOR) is reported. Furthermore, the ability of our newly developed NMP-based IL to grow MOF nanocubes on carbon nanotubes and MOF nano-islands on carbon fibers is also reported.

Expanding the Library: Twenty New Ln(III) Metal–Organic Frameworks, Including Two Isoreticular Pairs, from Dihaloterephthalic Acid

“…Since the first publication of benzenedicarboxylate (BDC/terephthalate)-based coordination polymers (CPs) in 1972, ten thousand six hundred and eighty-three (10,683) coordination networks derived from terephthalic acid have been reported. With a plethora of applications, including sensing of explosives, − heavy metals and other environmental pollutants, − catalysis, − imaging, , lighting, , and separation of harmful chemicals, − terephthalate-based CPs are widely studied and have opened several exciting possibilities for the development of functional materials. However, it was only recently, in 2002, that the first CPs with halogenated terephthalates were reported. − In addition to hydrogen bonding and π interactions, the presence of halogen atoms on the benzene ring can lead to halogen bonding, which drives supramolecular self-assembly and contributes to overall polymer stability. , Furthermore, since the halogen bond strengthens with increasing polarizability of the halogen atom in the order F < Cl < Br < I, halogen substitution presents a versatile tool for controlling/tuning network architecture and properties. − Inevitably, there is growing interest in halogenated CPs and metal–organic frameworks (MOFs), and as of the March 2024 update of the Cambridge Structural Database (CSD) version 5.45, there are seven hundred and three (703) coordination networks with halogenated terephthalate.…”

“…, a structure, uncharacterizable by SCXRD for Pr− Ho and {[Ln(DBrTA) 1.5 (DMF) 2 ]•DMF} ∞ , which was never seen with DClTA for Er(17), Tm(18), and Yb(19). All compounds are in the P 1 space group except 2−3, which belong to P21/n.…”