Carbon Nanostructures, Nanolayers, and Their Composites

The versatility of the arrangement of C atoms with the formation of different allotropes and phases has led to the discovery of several new structures with unique properties. Carbon nanomaterials are currently very attractive nanomaterials due to their unique physical, chemical, and biological properties. One of these is the development of superconductivity, for example, in graphite intercalated superconductors, single-walled carbon nanotubes, B-doped diamond, etc. Not only various forms of carbon materials but also carbon-related materials have aroused extraordinary theoretical and experimental interest. Hybrid carbon materials are good candidates for high current densities at low applied electric fields due to their negative electron affinity. The right combination of two different nanostructures, CNF or carbon nanotubes and nanoparticles, has led to some very interesting sensors with applications in electrochemical biosensors, biomolecules, and pharmaceutical compounds. Carbon materials have a number of unique properties. In order to increase their potential application and applicability in different industries and under different conditions, they are often combined with other types of material (most often polymers or metals). The resulting composite materials have significantly improved properties.

Synthesis of Hybrid Carbon Materials Consisting of N-Doped Microporous Carbon and Amorphous Carbon Nanotubes

The N-doped hybrid carbon materials containing amorphous carbon nanotubes (ACNTs) were obtained by free growth of a polymer at 200 °C. The improvement of electrical conductivity was achieved by a final carbonization at 600–800 °C under the flow of nitrogen. The microstructure of ACNT/N-doped hybrids was characterized using a transmission electron microscope and X-ray diffusion. Furthermore, their elemental composition was measured using energy-dispersive X-ray spectroscopy and an elemental analyzer. The experimental results indicated that the ACNTs had a diameter in the range of 40–60 nm and the N-doped carbon background contained nitrogen atoms in most bonded pyrrolic-N and quaternary-N groups. The results revealed that the microstructure of the as-grown nanotubes, prepared by the proposed method, is mainly amorphous. This technique introduces the advantages of low cost and process simplicity, which may redeem some drawbacks of the methods commonly used in ACNT synthesis.

A Novel Enzyme-Free Biosensor Based on Porous Core–Shell Metal Organic Frame Nanocomposites Modified Electrode for Highly Sensitive Detection of Uric Acid and Dopamine

A novel enzyme-free biosensor based on porous metal organic frame nanocomposites, i.e., core–shell structured Au@NC@GC nanocomposites, has been constructed for simultaneous determination of uric acid (UA) and dopamine (DA). Au@ZIF-8@ZIF-67 was prepared through a seed-mediated growth method and carbonized in nitrogen atmosphere to synthesize a nanoporous hybrid carbon materials (Au@NC@GC). Cyclic voltammetry (CV) and differential pulse voltammetry (DPV) studies demonstrate that the as-prepared Au@NC@GC modified glassy carbon electrode (Au@NC@GC-GCE) possesses a high selectivity and sensitivity for simultaneous detections of UA and DA. It exhibited wide linear responses for UA and DA in the range from 10 μM to 600 μM and 10 μM to 150 μM, with the detection limits of 0.773 nM and 0.746 nM, respectively (S/N = 3). Moreover, this novel electrochemical biosensor could be further utilized in biological analysis (i.e., human serum), and the satisfactory recovery results of UA and DA could be readily obtained. These afore-mentioned results further manifest that the as-prepared biosensors are capable for quantitatively monitoring UA and DA in serum, verifying the possibility for its future promising applications in real biological or clinic samples analysis.