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Surface-enhanced Raman spectroscopy (SERS) as a powerful analytical tool has gained extensive attention. Despite of many efforts in the design of SERS substrates, it remains a grand challenge for creating a general substrate that can detect diverse target analytes. Herein, we report our attempt to address this issue by constructing a novel metal-graphene oxide nanostructured film as SERS substrate. Taking advantages of the high affinity of graphene oxide (GO) toward aromatic molecules and the SERS property of nanostructured metal, this structure exhibits great potential for diverse aromatic molecules sensing, which is demonstrated by using crystal violet (CV) with positive charge, amaranth with negative charge, and neutral phosphorus triphenyl (PPh3) as model molecules.

An enhanced electrochemical sensing platform based on photoreduced graphene-polyoxometalate (PRG-POM) nanomaterials prepared by UV-assisted photoreduction method was developed for the simultaneous detection of hydroquinone (HQ), catechol (CT), and resorcinol (RS). Taking advantage of the combined benefits of graphene and POMs, these PRG-POMs nanomaterials showed fast electron-transfer kinetics for the Fe(CN)63−/4−redox system and prominent electrocatalytic activity for simultaneously determining the species mentioned above. With this sensing platform, the lowest concentration to quantify CT, HQ, and RS could be down to 40 nM, 50 nM and 90 nM, respectively. Furthermore, real samples including underground water and lake water were analyzed using the present sensing platform, and experimental results demonstrated that this electrochemical sensor exhibited excellent recoveries.

As a single-atom-thick carbon material with high surface area and conductivity, graphene provides an ideal platform for designing composite nanomaterials for high-performance electrocatalytic or electrochemical devices. Herein, we demonstrated a facile strategy for controllably growing high-quality Prussian blue nanocubes on the surface of reduced graphene oxide (PBNCs/rGO), which represents a new type of graphene/transition metal complex heterostructure. The merit of this method is that the composite nanomaterials could be produced directly from GO in an in situ wet-chemical reaction, where the reduction of GO and the deposition of PBNCs occurred simultaneously. The obtained composite nanomaterials were characterized by transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), thermogravimetric analysis (TGA), Raman spectroscopy, and electrochemical techniques. It was found that uniform PBNCs with controlled size and good dispersion were directly grown on the surface of graphene nanosheets. Moreover, we also investigated the performance of PBNCs/rGO nanocomposites as amperometric sensor toward reduction of H2O2. Such a sensor showed a rapid and highly sensitive response to H2O2with a low detection limit (45 nM), which might find promising applications in developing a new type of enzymeless biosensor.

A new kind of bismuth film modified electrode to sensitively detect trace metal ions based on incorporating highly conductive ionic liquids 1‐butyl‐3‐methyl‐imidazolium hexafluorophosphate (BMIMPF6) in solid matrices at glassy carbon (GC) was investigated. Poly(sodium 4‐styrenesulfonate) (PSS), silica, and Nafion were selected as the solid matrices. The electrochemical properties of the mixed films modified GC were evaluated. The electron transfer rate of Fe(CN)64−/Fe(CN)63−can be effectively improved at the PSS‐BMIMPF6modified GC. The bismuth modified PSS‐BMIMPF6composite film electrodes (GC/PSS‐BMIMPF6/BiFEs) displayed high mechanical stability and sensitive stripping voltammetric performances for the determination of trace metal cations. The GC/PSS‐BMIMPF6/BiFE exhibited well linear response to both Cd(II) and Pb(II) over a concentration range from 1.0 to 50 μg L−1. And the detection limits were 0.07 μg L−1for Cd(II) and 0.09 μg L−1for Pb(II) based on three times the standard deviation of the baseline with a preconcentration time of 120 s, respectively. Finally, the GC/PSS‐BMIMPF6/BiFEs were successfully applied to the determination of Cd(II) and Pb(II) in real sample, and the results of present method agreed well with those of atomic absorption spectroscopy.

To improve the reproducibility, stability, and sensitivity of bismuth film electrode (BiFE), we studied the performances of a mixed coating of two cation‐exchange polymers, Nafion (NA) and poly(sodium 4‐styrenesulfonate) (PSS), modified glassy carbon BiFE (GC/NA‐PSS/BiFE). The characteristics of GC/NA‐PSS/BiFE were investigated by scanning electron microscopy and cyclic voltammetry. Various parameters were studied in terms of their effect on the anodic stripping voltammetry (ASV) signals. Under optimized conditions, the limits of detection were 71 ng L−1for Cd(II) and 93 ng L−1for Pb(II) with a 10 min preconcentration. The results exhibited that GC/NA‐PSS/BiFE can be a reproducible and robust tool for monitor of trace metals by ASV rapidly and environmentally friendly, even in the presence of surface‐active compounds.