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MoS2 and nitrogen doped active carbon composite (MoS2/ANC) is fabricated to detect taxifolin and exhibits superior redox current response and decreased redox potential difference. Further investigation reveals that the kinetic process of the redox reaction of taxifolin on MoS2/ANC electrode is controlled by both adsorption and diffusion process. Under the optimum conditions, the redox peak currents linearly relate with the concentration of taxifolin in the range of 1 × 10−9–1 × 10−6 mol L−1, accompanied by the low detection limit (3 × 10−10 mol L−1). Meanwhile, outstanding selectivity, stability and repeatability are also obtained at MoS2/ANC electrode. At last, the proposed method is applied to quantitatively detect taxifolin in fructus polygoni orientalis and satisfactory results have been achieved.

Photocatalytic redox reactions occur on the surface of the catalyst, and therefore the surface properties of the photocatalyst are vital for efficient catalytic reactions. Bi2MoO6 surface co-doped with Ni2+ and Ti4+ ions was fabricated through an incipient-wetness impregnation technology and calcination method. The influence of Ni2+ and Ti4+ co-doping with different concentrations on the crystal structure, morphology, and optical properties of Bi2MoO6 were investigated by different instrumental methods, and the characterization results confirm that the surface of Bi2MoO6 was doped with Ni2+ and Ti4+ ions. Under visible-light irradiation, the effects of Ni2+ and Ti4+ surface co-doping on the photocatalytic activity of Bi2MoO6 were evaluated by the degradation of rhodamine B, with the results suggesting Ni2+ and Ti4+ co-doping increases visible-light absorption by Bi2MoO6 and promotes the separation of photogenerated charge carriers. With optimum Ni2+ and Ti4+ co-doping, Bi2MoO6 surface co-doped with 0.18% Ni2+ and 0.192% Ti4+ exhibits the greatest photocatalytic activity and stability in the degradation of rhodamine B.

A novel CC@MoS2-Ag3PO4 heterostructure, composed of Ag3PO4 nanoparticles decorated MoS2 nanosheets on carbon fiber cloth (CC), is fabricated by a simple hydrothermal method and a successive ionic layer absorption reaction. The CC@MoS2-Ag3PO4 heterostructure displays an excellent photocatalytic activity of ∼96% degradation rate for RhB solution under simulated daylight, which is more than 10 times as much as that of pure Ag3PO4 or MoS2. The CC@MoS2-Ag3PO4 heterostructure with optimized photoactivity is investigated by optical and electrochemical measurements. The CC@MoS2-Ag3PO4 heterostructure can not only broaden the photoresponse range of MoS2, but also alleviate the photodegradation of Ag3PO4, and the easily separated CC provides a proper conductive substrate and rapid charge transfer channels. The probable photocatalytic mechanism of CC@MoS2-Ag3PO4 heterostructure is discussed in detail. Therefore, the CC@MoS2-Ag3PO4 heterostructure with high efficient photocatalytic performance and easy separation is a promising photocatalytic material.

s A facile solution deposition method using the etched Cu2O truncated octahedrons as the substrates has been successfully demonstrated for tailoring Ag/Cu2O heterostructures with excellent reproducibility, and Ag nanoparticles have been deposited on the surface of different Cu2O particles including freshly prepared Cu2O truncated octahedrons, the etched Cu2O truncated octahedrons, Cu2O cube assemblies and Cu2O octahedron assemblies. The obtained tailoring Ag/Cu2O heterostructures prepared by the etched Cu2O truncated octahedrons exhibits enhanced photocatalytic activity for the degradation of MB solution under visible-light irradiation, and the photocatalytic activity of tailoring Ag/Cu2O heterostructures was 3.1 and 5.7 times higher than those of the etched Cu2O truncated octahedrons and bare Cu2O truncated octahedrons. The enhanced photocatalytic activity of tailoring Ag/Cu2O heterostructures can be attributed to tailoring surface of Cu2O truncated octahedrons, the enhancement of UV–vis absorbance spectra and electron sink effect due to Ag nanoparticle deposition. The facilely prepared tailoring Ag/Cu2O heterostructure products are promising materials in fields such as photocatalytic and optoelectronic applications.

Cobalt and zinc bi-metal organic frameworks (CoZn-MOF) derived from double metal hydroxides (CoZn-DMH) is synthesized on the surface of rice husk carbon via hydrothermal method. The obtained CoZn-MOF/RHC is then used as electrochemical sensor for dopamine detection. SEM and TEM characterization displays that the morphology of CoZn-MOF/RHC is different from CoZn-DMH, as well as the electrochemical performance. Further investigation reveals that the kinetic process of the redox reaction of dopamine on CoZn-MOF/RHC electrode is controlled by diffusion process. Under the optimum conditions, the redox peak current linearly relates with the concentration of dopamine in the range of 2 μM~0.8 mM, with the low detection limit of 0.67 μM. During the anti-interference experiment, CoZn-MOF/RHC exhibits good selectivity toward dopamine detection but inappreciable response for interferent.

Nickel-based metal organic framework (Ni-MOF) and carbon nanotubes composite (Ni-MOF/CNTs) is constructed via in situ self-assembly of Ni-MOF in the presence of CNTs solution. The obtained electrode (Ni-MOF/CNTs) exhibits sensitive response toward the detection of taxifolin by significantly enhancing the redox peak currents and decreasing the peak-to-peak separation. Under the selected conditions, the peak current linearly relates with taxifolin concentration in the range of 4.0 × 10−8 ~ 1.0 × 10−5 mol L−1 with the detection limit of 1.33 × 10−8 mol L−1 (S/N = 3). Otherwise, the lithium storage results reveal that Ni-MOF/CNTs with enhanced conductivity exhibits benign cycling stability and rate capability, with coulomb efficiency around 100%. This Ni-MOF/CNTs electrode may lay the foundation for the Ni-MOF based materials in electrochemical application.

CuS/CuO nanowire heterostructures grown on copper mesh (CuS/CuO/Cu) have been successfully synthesized by a liquid–solid reaction at room temperature followed by annealing. The proposed structure has been verified by X-ray diffraction analysis. Scanning electron microscopy images have indicated that the density and diameter of CuS nanoparticles on CuO nanowires can be tuned by controlling the duration of sulfonation with Na2S. Photocatalytic studies have revealed that CuS/CuO/Cu heterostructures offer improved photocatalytic activity in the degradation of Methylene Blue (MB) in the presence of H2O2. A sample designated as CuS/CuO/Cu-10, where “10” denotes sulfonation with Na2S for 10 min, showed the best photocatalytic properties, with MB degradation efficiencies under visible light irradiation of 87.4% after 20 min and 98.6% after 40 min. The enhanced photocatalytic activity can be attributed to effective electron–hole separation and improved visible light utilization due to the cooperative effect of the CuS/CuO heterostructures and conductive copper mesh.

A simple one-pot hydrothermal route has been demonstrated for the fabrication of 3D ZnO@hemimorphite zinc silicate (ZSO) core–shell nano-heterostructures on the Si substrate. Individual 3D ZnO@ZSO core–shell nano-heterostructures were assembled with many bundle-like branches, and each bundle-like branch was composed of the ZnO rod as the core and ZSO nanowires as the shell. The structure and composition of the 3D ZnO@ZSO nano-heterostructures could be varied with different reaction conditions and exhibit excellent reproducibility as well. In addition, a possible mechanism for the fabrication of 3D ZnO@ZSO nanohybrids was proposed, suggesting that heterogeneous nucleation played important roles in the formation of 3D nanostructures. The resultant 3D ZnO@ZSO nano-heterostructure films exhibited hydrophobic adhesive characteristic with a water contact angle of 142.1° and a high contact angle hysteresis, which held a great potential in surface wettability and other opto-electronic applications.

A graphene-based device requires the graphene to have an ideal shape, structure, and orientation, and be large enough, to allow them to be formed into a new device. Here the joining of individual single-layer and multi-layer graphene is performed in a transmission electron microscope-scanning tunneling microscope (TEM–STM) holder inside a 200 kV field emission TEM. Attempts have been made to join individual graphene sheets (GSs) with the so-called “top-to-top” and “layer-to-layer” geometries by applying a voltage. In the two geometries, the “top-to-top” form has resulted in a seamless joining for both single-layer and multi-layer GSs. The as-joined GSs show the same excellent electrical and mechanical properties as those of the original GSs. Large Joule heating originating from the field emission current will cause atom diffusion and self-assembly and then rearrangement of carbon networks at the GS edge front. In this way individual GSs could be extended and mended with the so-called “top-to-top” geometries by applying a constant voltage, to meet the required and desired shape, size, configuration, and functions for a variety of the special micro/nano scaled devices.

A simple hydrothermal method has been developed for fabricating hemimorphite zinc silicate, Zn 4 Si 2 O 7 (OH) 2 ·H 2 O (ZSO). Three-dimensional ZSO hierarchal superstructures are deposited on the Si substrate. The product is characterized by X-ray diffraction, scanning electron microscopy, and transmission electron microscope. The characterization results of the sample show individual ZSO hierarchical architectures are assembled by many well-aligned and highly ordered rod bundles. The morphologies of the rod bundles within the ZSO hierarchal superstructures can be conveniently controlled, by selecting the different reactant concentrations, with excellent reproducibility. The luminescence spectra showed that the ZSO hierarchical superstructure had a stronger emission peak at 436 nm and a weaker emission peak at 418 nm.