Novel single-crystalline ZnO nanosheets with porous structure have been fabricated by annealing ZnS(en)(0.5) (en = ethylenediamine) complex precursor. The morphology and structure observations performed by field emission scanning electronic microscopy (FESEM) and high-resolution transmission electron microscopy (HRTEM) indicate that numerous mesopores with a diameter of about 26.1 nm distribute all through each nanosheet with a high density. The transformation of structure and composition of samples obtained during thermal treatment processes were investigated by x-ray diffraction (XRD), x-ray photoelectron spectrometry (XPS), thermogravimetric analysis (TGA), and Fourier transform infrared (FTIR) absorption spectroscopy. The formation mechanism of the porous structure is proposed. For indoor air contaminant detection in which formaldehyde and ammonia are employed as target gases, the as-prepared ZnO nanosheets were applied for the fabrication of gas sensors. It was found that the as-fabricated sensors not only exhibit highly sensitive performance, e.g., high gas-sensing responses, short response and recovery time, but also possess significant long-term stability. It is indicated that these ZnO nanostructures could promisingly be applied in electronic devices for environmental evaluation.

A Ti3C2QD-based fluorescent probe for an ALP activity assay and embryonic stem cell identification was developed by taking advantage of the inner filter effect.

Hollow and porous In(2)O(3) nanospheres have been prepared by the hydrolysis of InCl(3) using carbonaceous spheres as templates in combination with calcination. Based on the observation of scanning electronic microscopy (SEM) and transmission electron microscopy (TEM), it has been revealed that the as-prepared In(2)O(3) nanospheres have a uniform diameter of around 200 nm and hollow structures with thin shells of about 30 nm consisting of numerous nanocrystals and nanopores. Owing to the hollow and porous structures, In(2)O(3) nanospheres possessing more active surface area exhibit a good response and reversibility to some organic gases such as methanol, alcohol, acetone and ethyl ether. In addition, the response mechanism of hollow and porous In(2)O(3) nanospheres to organic gases has been proposed. Furthermore, these prepared In(2)O(3) spheres showed a UV-visible absorption peak centered at around 309 nm, and their photoluminescence spectra have also been investigated.

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Application of copper nanowires (Cu NWs) for interconnects in future nanodevices must meet the following needs: environmental stability and superior electrical transport properties. Here, we demonstrate a kind of Cu NW that possesses the both properties. The Cu NWs were synthesized through a hydrothermal route with the reduction of copper chloride using octadecylamine (ODA). The reasons for their environmental stability could be due to interaction of ODA(+) molecules with the surface of Cu NWs and forming strong N-Cu chemical bonds. Electrical transport properties of individual Cu NW were investigated by using the four-probe measurement, showing the temperature-dependent resistance of the Cu NW was fairly linear in the temperature range from 25 to 300 K and the Cu NW retained the low resistivity of approximately 3.5 × 10(-6) Ω · cm at room temperature, near the resistivity value of bulk copper. The maximum transport current density for the Cu NW should be superior to 1.06 × 10(7) A · cm(-2). In addition, the Cu NWs have ultralow junction resistance. The present study indicates that the Cu NWs could act as a multifunctional building blocks for interconnects in future nanoscale devices.

A new kind of SnO2 nanotubes loaded with Ag2O nanoparticles can be synthesized by using Ag@C coaxial nanocables as sacrificial templates. The composition of silver in SnO2 nanotubes can be controlled by tuning the compositions of metallic Ag in Ag@C sacrificial templates, and the morphology of tubular structures can be changed by use of nanocables with different thicknesses of carbonaceous layer. This simple strategy is expected to be extended for the fabrication of similar metal‐oxide doped nanotubes using different nanocable templates. In contrast to SnO2@Ag@C nanocables as well as to other types of SnO2 reported previously, the Ag2O‐doped SnO2 nanotubes exhibit excellent gas sensing behaviors. The dynamic transients of the sensors demonstrated both their ultra‐fast response (1–2 s) and ultra‐fast recovery (2–4 s) towards ethanol, and response (1–4 s) and recovery (4–5 s) towards butanone. The combination of SnO2 tubular structure and catalytic activity of Ag2O dopants gives a very attractive sensing behavior for applications as real‐time monitoring gas sensors with ultra‐fast responding and recovering speed.

Most gold nanoparticle-based electrodes have been utilized for the analysis of highly toxic As(III), while nano-Fe3O4 materials are currently attracting considerable interest as an adsorbent for the removal of As(III). However, the combination of gold nanoparticles with Fe3O4 nanoadsorbents for stripping voltammetry is, to the best of our knowledge, unexplored. Here, a sensing interface for ultrasensitive detection of As(III) is designed and constructed by abundantly dispersing Au nanoparticles (Au NPs) on the surface of the Fe3O4 nanosphere. The Au@Fe3O4 nanospheres are covered by the room temperature ionic liquid (RTIL) and then modified on the screen-printed carbon electrode (SPCE). By combining the excellent catalytic properties of the Au nanoparticles (∼3-9 nm in diameter) with the good adsorption capacity of Fe3O4 nanospheres toward As(III), as well as the good conductivity of RTIL, the Au@Fe3O4-RTIL shows excellent performance in the detection of arsenic under nearly neutral conditions without modifying the morphology of the sensing interface. Through optimization of the experimental conditions, an ultrahigh sensitivity of 458.66 μA ppb(-1) cm(-2) from 0.1 to 1 ppb with a detection limit (3σ method) of 0.0022 ppb was obtained. The reproducibility and reliability of the Au@Fe3O4-RTIL sensing interface was also evaluated with good results. Finally, we used this platform to analyze real samples.

It has been reported that the majority of groundwater shows weak alkaline in which the As(III) species would be present as neutral HAsO species and ionized HAsO species. However, as most reported previously, electrochemical detection of As(III) has been operated under acidic conditions and the nonionic As(III) (HAsO) is the dominant species. Therefore, considering the change of As(III) speciation in different pH conditions, to develop a reliable method for the detection of As(III) in alkaline media might be more meaningful for practical applications. Here, combined the multilayer adsorption of nanorod-like α-MnO with the excellent electrocatalytic ability of ∼5 nm Au nanoparticles (AuNPs), an efficient and ultrahigh anti-interference electrochemical detection of As(III) with AuNPs/α-MnO nanocomposite in alkaline media (nearly real water environment) was developed. Notably, we have provided a thorough electrochemical analytical investigation to confirm the advantage of As(III) detection in alkaline media. The system was evaluated by a series of interference tests, and no obvious interference from commonly coexisting substances (referring to the groundwater, Togtoh region, Inner Mongolia, China) was observed in alkaline media. Furthermore, electrodes robust stability and excellent reproducibility were obtained. Under the optimized conditions, the limit of detection (3σ method) toward As(III) was 0.019 ppb, and the obtained sensitivity was 16.268 ± 0.242 μA ppb cm. Finally, the proposed method has been successfully employed for detection of As(III) in a real water sample.