MIL-100(Fe) Metal–Organic Framework Nanospheres Embedded in Graphene Matrixes for Xanthine Fluorescence Sensing

Abstract

Study and application of MIL-100­(Fe)-based two-dimensional graphene oxide (GO) nanocomposite was limited because the nucleation of the spherical structure of MIL-100­(Fe) on GO along different directions hindered the formation of MOF-100­(Fe). To address this issue, MIL-100­(Fe)/three-dimensional graphene (3DG) nanocomposites (abbreviated as MIL-3DG-n, n = 25, 50, 75, and 100) were successfully fabricated via in situ growth of MIL-100­(Fe) on 3DG matrixes in this work because the unique structure of 3DG can avoid the attachment with MIL-100­(Fe) on nucleation sites along multiple directions, resulting in their ideal combination. The prepared MIL-3DG nanocomposites exhibited higher peroxidase-like catalytic activities than pure MIL-100­(Fe), and MIL-3DG-75 exhibited the best peroxidase-like activities for detecting xanthine with the detection limit of 0.0014 μM in the linear range of 0–200 μM to date, to the best of our knowledge, which is attributed to the higher affinity of MIL-3DG-75 nanocomposite to peroxidase substrates o-phenylenediamine (OPD) and H2O2, confirmed by the Michaelis–Menten kinetics (V m: 49.5 × 10–8 M s–1 for H2O2, 18 × 10–8 M s–1 for OPD, K m: 0.029 mM for H2O2, 0.011 mM for OPD). Owing to the high catalytic efficiency of the MIL-3DG-75 nanocomposite, a rapid and efficient strategy for the sensitive colorimetric detection of xanthine was established.

Highly efficient peroxidase-like activity of a metal–oxide-incorporated CeO2–MIL(Fe) metal–organic framework and its application in the colorimetric detection of melamine and mercury ions via induced hydrogen and covalent bonds

“…3b shows numerous deconvoluted peaks, with those at 881, 889.4, 906.6 and 917.7 eV matching the Ce 4+ oxidation state and the peak at around 899.4 corresponding to the Ce 3+ oxidation state of the cerium ions. In the high-resolution Fe 2p spectrum of CeO 2 –MIL(Fe), two major peaks at 727.0 and 713.0 eV match the binding energies of Fe 2p 1/2 and Fe 2p 3/2 derived from MIL(Fe), respectively 25–27 (Fig. 3c).…”

Increasing the peroxidase-like activity of the MIL-100(Fe) nanozyme by encapsulating Keggin-type 12-phosphomolybdate and covering three-dimensional graphene

“…For 3DGO, there is a broad diffraction peak at 24°, indicating that 3DGO is successfully synthesized. 28 The pattern of MIL-100(Fe) @PMo 12 @3DGO shows that peaks appear at 11.0°, 14.1°, 18.6°, 20.1°, and 24.1°, containing the peaks of MIL-100(Fe) @PMo 12 and 3DGO. The IR spectra of MIL-100(Fe), MIL-100 (Fe)@PMo 12 , 3DGO and MIL-100(Fe)@PMo 12 @3DGO are shown in Fig.…”

A series of novel Cu-based MOFs: syntheses, structural diversity, catalytic properties and mimic peroxidase activity for colorimetric detection of H2O2

“…This means that MOFs first reacted with one substrate, then emancipated the product before reacting with the other substrate. 50,51 The mechanism of the catalytic reaction was speculated to be the decomposition of H 2 O 2 into OH in the presence of Cu-MOFs. Copper with multiple valence states or coordination numbers can activate H 2 O 2 to generate OH.…”