This paper presents the first successful application of vinyl polymer/graphene-based nanocomposites in corrosion protection. Well-dispersed polystyrene (PS)/modified-GO nanocomposites were successfully prepared using in situ miniemulsion polymerisation. The as-prepared nanocomposites exhibit superior anti-corrosion properties compared with pure PS, in which the corrosion protection efficiency increased from 37.90% to 99.53% with the incorporation of 2 wt% modified GO in the PS polymer matrix. The thermal stability and mechanical properties also greatly improved compared with pure PS. The incorporation of 2 wt% modified GO in the PS polymer matrix increased the thermal decomposition temperature (T_d) from approximately 298 to 372 °C, and the storage modulus increased from 1808.76 to 2802.36 MPa. This paper attributes the substantially improved properties to the nearly complete exfoliation of the modified-GO dispersion, which greatly enhanced the modified-GO/PS interfacial bond strength and gas barrier properties.

We report a novel electrochemical sensor for the sensitive and selective determination of the antipsychotic drug chlorpromazine (CPZ) based on the iron (Fe) nanoparticles-loaded graphene oxide (GO-Fe)/three dimensional (3D) honeycomb-like zinc oxide (ZnO) nanohybrid modified screen printed carbon electrode (SPCE). The 3D hierarchical honeycomb-like ZnO was synthesized using a novel aqueous hydrothermal method and the GO-Fe/ZnO nanohybrid was prepared based on an inexpensive and fast sonochemical method using a high-intensity ultrasonic bath (Delta DC200H, 200 W, 40 KHz). Characterizations including scanning electron microscopy, elemental mapping, transmission electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy, and Raman spectroscopy were carried out as part of this work. The electrocatalytic oxidation behavior of CPZ at various electrodes was investigated using the cyclic voltammetry technique, through which the GO-Fe/ZnO modified SPCE was identified as the best performing electrode. The quantitative determination of CPZ was then performed using the differential pulse voltammetry technique. The as-prepared GO-Fe/ZnO/SPCE sensor exhibited a quick and sensitive response towards the oxidation of CPZ with linear concentration ranges from 0.02 to 172.74 μM and 222.48 to 1047.74 μM. The modified SPCE sensor displayed a low detection limit (LOD) of 0.02 µM and a high sensitivity of 7.56 µA µM^-1 cm^-2. The proposed sensor also showed remarkable operational and storage stability, reproducibility, and repeatability. Furthermore, the practicability of the GO-Fe/ZnO/SPCE sensor has been verified with real sample analysis using commercial antipsychotic CPZ tablets and human urine samples, and adequate recovery has been achieved.

A novel sorbent Cu-S metal-organic framework (MOF) microrods was prepared for dispersive solid-phase extraction via microwave synthesis and used to determine 12 fluoroquinolones (FQs) in honey samples employing ultrahigh-performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS). The best extraction efficiency was achieved by optimizing sample pH, sorbent quantity, eluent type/volume, and extraction and elution time. The proposed MOF exhibits advantages such as rapid synthesis time (20 min) and outstanding adsorption ability toward zwitterionic FQs. These advantages can be attributed to multiple interactions, including hydrogen bonding, π-π interaction, and hydrophobic interaction. The limits of detection of analytes were 0.005-0.045 ng g^-1. Acceptable recoveries (79.3%-95.6%) were obtained under the optimal conditions. Precision (relative standard deviation, RSD) was <9.2%. These results demonstrate the utility of our sample preparation method and the high capacity of Cu-S MOF microrods for rapid and selective extraction of FQs from honey samples.

Glycine-modified graphene oxide (GMGO) and its derivative, nanogold-deposited graphene oxide (AuGO), were prepared and then embedded into the matrix of poly(vinyl alcohol) (PVA) nanofibres by electrospinning. The scanning electron microscopy images showed that the morphologies of the nanofibres were improved by the incorporation of GMGO at a low loading content (e.g., 0.1–0.5 wt%) compared with pure electrospun PVA. The two-dimensional, high-aspect ratio GMGO sheets were folded into the nanofibres with a diameter smaller than 150 nm; the microstructures were evaluated using high-resolution transmission electron microscopy. Performing X-ray diffraction analysis revealed that the GMGO-incorporated nanofibres exhibited increased crystallinity. Substantially improved properties, particularly conductivity, mechanical strength, and thermal stability, of PVA electrospun nanofibres embedded with GMGO and AuGO were demonstrated. Analysing PVA composite fibre mats using an electrochemical impedance spectrometer revealed that embedding with GMGO decreased impedance, and that embedding with AuGO decreased it even further. The storage modulus increased by 50.5% and the thermal decomposition temperature increased by approximately 20 °C in the 0.5 wt% GMGO/PVA electrospun nanofibre mats compared with pure PVA nanofibres. Cellular toxicity tests of these electrospun nanofibres showed almost no cytotoxicity to L929 cells.

Facilely synthesized peroxidase-like nanozymes with high catalytic activity and stability may serve as effective biocatalysts. The present study synthesizes peroxidase-like nanozymes with multinuclear active sites using two-dimensional (2D) metal-organic framework (MOF) nanosheets and evaluates them for their practical applications. A simple method involving a one-pot bottom-up reflux reaction is developed for the mass synthesis of (Cu-S)_n MOF 2D nanosheets, significantly increasing production quantity and reducing reaction time compared to traditional autoclave methods. The (Cu-S)_n MOF 2D nanosheets with the unique coordination of Cu(I) stabilized in Cu-based MOFs demonstrate impressive activity in mimicking natural peroxidase. The active sites of the peroxidase-like activity of (Cu-S)_n MOF 2D nanosheets were predominantly verified as Cu(I) rather than Cu(II) of other Cu-based MOFs. The cost-effective and long-term stability of (Cu-S)_n MOF 2D nanosheets make them suitable for practical applications. Furthermore, the inhibition of the peroxidase-like activity of (Cu-S)_n MOF nanosheets by glutathione (GSH) could provide a simple strategy for colorimetric detection of GSH against other amino acids. This work remarkably extends the utilization of (Cu-S)_n MOF 2D nanosheets in biosensing, revealing the potential for 2D (Cu-S)_n MOFs.