Conductive 2D Metal‐organic Framework (Co, NiCo, Ni) Nanosheets for Enhanced Non‐enzymatic Detection of Urea

Abstract

2D metal‐organic framework (MOF) has potential applications in electrocatalysis owing to fast mass transfer, charge transfer and large specific surface area. Here, we had prepared three conductive 2D MOF based on Ni, NiCo and Co in a simple and rapid way. The 2D nanostructure of MOF was confirmed by SEM and TEM. The chemical composition was studied by XRD, Raman and XPS spectrum. The electrochemical oxidation and detection was investigated through cyclic voltammetry and current‐time method. Their sensing performance for urea was determined by varying oxidation potentials and metal sites. The non‐enzymatic Ni‐, NiCo‐ and Co‐MOF sensors had good catalytic activity for urea. Compared with NiCo‐ and Co‐MOF, Ni‐MOF had a wider linear range (0.5–832.5 μM), high sensitivity (1960 μA mM−1 cm−2), low detection limit (0.471 μM), and fast response time. The sensors had well repeatability, reproducibility, and selectivity to specific interfering species. Furthermore, Ni‐ and NiCo‐MOF modified electrode was also applied to detection of milk samples. The results showed that the recovery was satisfactory, which further confirmed the effectiveness of non‐enzyme sensor. In general, the highly‐sensitive 2D Ni‐ and NiCo‐MOF modified electrode has great potential as nonenzymatic urea sensors for real samples detection in hydrogen energy, clinical diagnostics, and environmental protection, et al.

Tunable Preparation of SERS-Active Au–Ag Janus@Au NPs for Label-Free Staphylococcal Enterotoxin C Detection

“…As demonstrated in Figure 4c, NiCo-MOF NSs showed distinct characteristic peaks at 633, 861, 1135, 1428, and 1612 cm −1 , and the positions of these characteristic peaks were the same as those reported in the literature. 39 Obviously, the Raman intensity of all these characteristic peaks did not change significantly under different conditions, which further proved the strong stability of the asprepared NiCo-MOF NSs. Magnetic Fe 3 O 4 NPs were designed to in situ grow on the surface of NiCo-MOF NSs.…”

“…To further investigate the stability of NiCo-MOF NSs, the SERS spectra of NiCo-MOF NSs were tested by varying the conditions of storage times (0 day and 270 days), temperatures (20, 40, and 60 °C), and pH (4, 5, 6, and 7). As demonstrated in Figure c, NiCo-MOF NSs showed distinct characteristic peaks at 633, 861, 1135, 1428, and 1612 cm –1 , and the positions of these characteristic peaks were the same as those reported in the literature . Obviously, the Raman intensity of all these characteristic peaks did not change significantly under different conditions, which further proved the strong stability of the as-prepared NiCo-MOF NSs.…”

NiO/Ni Metal–Organic Framework Nanostructures for Asymmetric Supercapacitors

“…36 As for Ni-MOF, the peak at 632 cm −1 was the tensile response of the metal Ni after coordination with O. 37 The peaks at ca. 860 and 1138 cm −1 were associated with the plane deformation of the C−H in aromatic ring and CO stretching of the terephthalic ligand, respectively, and peaks at 1434 and 1615 cm NiO core could expose more active sites into the electrolyte in contrast to the self-stacking Ni-MOF alone.…”

“…A peak at 519 cm –1 for NiO was related to the one-phonon (1 P) mode in NiO . As for Ni-MOF, the peak at 632 cm –1 was the tensile response of the metal Ni after coordination with O . The peaks at ca.…”

Two‐dimensional MOFs: Design & Synthesis and Applications

“…prepared three Ni, Nico and Co based conductive 2D MOFs in a simple way. Non enzymatic Ni‐MOF, NiCo‐MOF and Co‐MOF sensors have good catalytic activity for urea [126] . Furthermore, 2D Ni‐MOF and NiCo‐MOF modified electrodes have high sensitivity, good repeatability, reproducibility and high selectivity as non‐enzymatic urea sensors.…”