Nano

Due to the high theoretical capacity of sulfur (1675mAh${\text{g}}^{-1})$, low cost and environmental friendliness, lithium-sulfur batteries have shown broad prospects in future energy conversion and storage systems. However, the shuttle effect and insulating properties of sulfur restrict its practical application. Herein, we report a facile approach to fabricate Al-TDC@S-PPy composite material as lithium-sulfur battery electrode. In this strategy, a topological porous Al-TDC ($\mathrm{\text{TDC}}=2$,5-thiophenedicarboxylate) with 8-connected clusters is reported, which can provide strong adsorption for dissolved intermediate polysulfides and alleviate volume expansion. Meanwhile, Polypyrrole, (PPy) as a conductive and flexible additive to expedite electron transport, improves electrical conductivity. Consequently, the Al-TDC@S-PPy composite cathode exhibits a higher initial specific capacity (1310.4mAh${\text{g}}^{-1}$ at 0.2C). The final reversible capacity is 411.0mAh${\text{g}}^{-1}$ after 200 cycles at 1 C. We can extend this strategy to other metal-organic frameworks (MOFs) and manufacture MOF/conductive polymer composite electrodes for high-performance lithium-sulfur batteries.

Currently, with the increasingly serious pollution problem of oily wastewater, it is urgent to develop advanced materials and methods. In this work, a Fe(III)-CMC@Ni(OH)₂@Ni composite foam with superhydrophilic and underwater superoleophobicity was fabricated by an in situ growth of flower-like Ni(OH)₂ nanoparticles and chelated assembly of Fe(III)-CMC nanohydrogel via a layer-by-layer self assembly using ${\text{Fe}}^{3+}$ ion and carboxymethyl cellulose (CMC). The composite foam could separate various oil/water mixtures and exhibited excellent efficiency over 99%. This foam possessed ultrahigh water flux (220000L ${\text{m}}^{-2}$ ${\text{h}}^{-1})$ and better resistant to penetration pressure (1.3kPa). After 30 cycles, the oil–water separation performance reduced only 0.5%, but the foam structure was still stable that guarantees a better lifetime. Besides, this composite foam showed anti-fouling, unique durability and excellent corrosion resistance performance. Taking into account all good properties, Fe(III)-CMC@Ni(OH)₂@Ni composite foam was expected to be a potential candidate for responding to all kinds of complex oily wastewater conditions.

In recent years, intensive researches have been stimulated to explore the promising prospect for carbon nanotubes (CNTs) in the fabrication of novel polymer sensor composites. In this study, the fabrication and properties of a flexible and stretchable composite elastomer fabricated from direct-spun carbon nanotube fiber (yarns) were presented, and the novel CNT fiber/polydimethylsiloxane (PDMS) elastic conductive composite shows the reversible two-stage conductivity owing to its unique structure of CNTs fabricated by the floating catalyst chemical vapor deposition (FCCVD). As the strain increased from 0% to 10% (Stage I), stretching the oriented CNT fiber/PDMS elastic conductive composite induces a constant decrease in the conductive pathways and contact areas between CNTs depending on the stretching distance. However, this composite elastomer will retain almost stable electrical resistance while being stretched by over 10% (Stage II). Furthermore, the composite shows very little variation in resistance under 187 stretching–releasing cycles up to a pre-strain level of 6%, indicating the outstanding stability and repeatability in performance as stretchable conductors. The microstructure, reversible two-stage conductive properties and mechanism were also discussed.

The presence of the antibiotics in the wastewater has posed a huge risk to aquatic life and human health. It is a great significance to develop an effective technology to treat the antibiotics-containing wastewater. In this study, a series of g-C₃N₄/NH₂-MIL-88B(Fe) composite photocatalysts are synthesized through a simple one-step method. The structure and optical properties of prepared photocatalysts are detected by X-ray diffraction (XRD), field emission scanning electron microscope (FESEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), UV–Vis absorption spectra (UV–Vis DRS), photoluminescence (PL) spectroscopy and transient photocurrent techniques, respectively. FESEM and TEM show that MOF is uniformly dispersed in petaloid g-C₃N₄. The uniform dispersion of Fe-MOFs in the heterojunction composites increases the specific surface area ($S_{\mathrm{\text{BET}}})$ of g-C₃N₄, which results in a great adsorption property for the nanocomposite. The capture experiment shows that $•$${\text{O}}_2^{-}$ and ${\text{h}}^{+}$ are the main active substances in ciprofloxacin (CIP) degradation. These prepared composite photocatalysts exhibit excellent CIP photodegradation activity under visibly light irradiation with an apparent rate constant of 0.0127${\text{min}}^{-1}$ (3.74 times as the rate of single component). The remarkable catalytic performance can be ascribed to the fact that the g-C₃N₄/NH₂-MIL-88B(Fe) heterojunction inhibits the recombination of photoinduced electron–hole pairs and improved the visible light absorption.

Through a replacement reaction approach, Ag nanostructure was easily prepared on economical digital video disc (DVD) and polydimethysiloxane (PDMS) with surface structure duplicating from the former. Distinct nanoscale morphology was observed, featuring intersecting Ag nanoplates with abundant hot spots on the DVD and spherical Ag nanoparticles on the PDMS. Surface-enhanced Raman scattering (SERS) spectra, using crystal violet as a probe, revealed a superior enhancement effect in Ag/DVD versus that in Ag/PDMS. Considering the desirable flexibility and transparency of PDMS for in situ detection, we further developed a protocol to introduce intersecting Ag nanoplates onto the PDMS surface. The resulting Ag/PDMS substrate was endowed with remarkable sensitivity, excellent uniformity and good stability under mechanical bending. Furthermore, effective in situ detection of malachite green on fish was demonstrated, highlighting the great potential of our approach for the in situ detection of target molecules on a curved surface.

Ultramarine is a nontoxic and cheap inorganic pigment, which has been rarely used in blue pearlescent pigments. This work reports the synthesis of nano-ultramarine with LTA structure by calcining the polysulfide impregnated zeolite at 600^∘C for 1h. Then the ultramarine colored mica composite was prepared by using $\gamma$-(2,3-epoxypropoxy) propytrimethoxysilane (KH-560) to attach ultramarine to the mica substrate through a covalent bond. Scanning electron microscope with energy dispersive spectrometer (SEM-EDS), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and Ultraviolet and Visible Spectrophotometry (UV-Vis) were employed to characterize the structure and properties of the ultramarine, composites as well as the intermediates. The results showed that LTA framework was retained in ultramarine during the calcination at the temperature below 700^∘C. The FTIR spectra demonstrated that ultramarine was successfully modified by KH-560. The SEM, UV-Vis and $L$*$a$*$b$* values revealed the increasing the amount of KH-560-modified ultramarine contributing to the formation of the dense coating layer on mica and changed the color of the ultramarine-coated mica composite. The optimum mass ratio of mica to ultramarine was 1:2 and the composite demonstrated an ideal blue pearlescent effect.

The X-ray fluorescence spectroscopy (XRF) has been widely applied on the analysis of elements. The traditional sample preparation needs a large sample weight and high temperature/pressure. To overcome these drawbacks, we used graphene oxide (GO) as a matrix for the carry of trace metal (copper was used as a model) and constructed a sandwich-layered GO which carried trace copper nanomembrane (SL-GO-Cu). After the optimization of filter membranes, nanomembrane composition and GO content in the bottom layer of SL-GO-Cu, the limit of detection (LOD) of SL-GO-Cu achieves 2.99 $\mu$g/g. The LOD is ca. 1/3 or 1/1923 of the traditional melt pellets of trace CuO (MPT-Cu) and tabletting pellets of trace CuO (TPT-Cu) methods, respectively. The SL-GO-Cu is independent of CuO size, but varies with different Cu compounds. Recoveries of all the SL-GO-Cu samples prepared above are higher than 94% and do not show significant difference. In summary, the SL-GO-Cu is a promising method for the efficient and economical determination of trace elements.

Gold nanoparticles (AuNPs)-decorated reduced graphene oxide (rGO) is a compelling material from both aspects of processing and functionality. This paper presents an alternative method to prepare and alter the optoelectronic properties of the AuNPs-rGO hybrid film. Au was sputtered for a duration of 0–60 s on graphene oxide (GO) film before subjected to thermal reduction at 700^∘C. The surface of rGO was decorated by spherical AuNPs with a mean particle size of around 10nm due to the solid-state dewetting process. The surface plasmon resonance (SPR) of AuNPs around 550nm was intense when the Au sputter duration exceeded 20s. Remarkably, the AuNPs layer retarded the de-oxygenation of GO during thermal annealing. The AuNPs-rGO hybrid film with long-duration Au sputtering exhibited low optical constants and thicker rGO film. The AuNPs also played the role in lowering the bandgap, increasing the lattice disorder and assisting the high-energy photon absorption in the thermally reduced rGO film. The sample of 30s and 40s Au sputtering was optimum to obtain the lowest sheet resistance of 59k$\mathrm{\Omega }$/sq and 56k$\mathrm{\Omega }$/sq, respectively. The sheet resistance was bargained between de-oxygenation retardation and doping by the AuNPs. Both samples of 30 s and 40 s Au sputtering were having a unique and satisfyingly strong absorption band around 260nm, 350nm and 555nm corresponding to $n-\pi$* transition, $\pi -\pi$* transition and SPR of AuNPs, respectively. Such properties are desirable in several applications such as a transparent electrode and optoelectronic sensor.

For the treatment of dye wastewater, it is of great significance to develop new adsorbents with high adsorption capacity and good separation effect. In this study, the Fe-Co magnetic activated carbon material (CN-Fe-Co-AC) was first prepared by high-temperature calcination. CN-Fe-Co-AC is physically characterized by various methods. CN-Fe-Co-AC can efficiently and quickly remove the organic dyes methylene blue (MB) and acid blue 80 (AB80). The adsorption of MB and acid blue based on CN-Fe-Co-AC adsorbent is mainly through the specific surface area and the functional groups on the surface. During this recovery process, the adsorption activity of CN-Fe-Co-AC for MB and AB80 decreased slightly. Kinetic data can be described using a Pseudo-second-order model and the data for adsorption equilibrium can be described using the Langmuir isotherm. The theoretical adsorption capacities of MB and AB80 are 104.82mg/g and 26.94mg/g, respectively. After repeated use of five times, the removal rate of MB exceeded 96%, and the removal rate of AB80 exceeded 75%. The excellent adsorption performance and recyclability of CN-Fe-Co-AC indicate that this material has certain potential application value.

An important attribute of microRNA-205 (MiR-205) is their potential use as predictive biomarker for anti-radiation of nasopharyngeal carcinoma (NPC), and it is pivotal to monitor the dynamic change of MiR-205 for personalized precise treatment strategies. So far, there are several methods aiming at detecting MiR-205 while rarely has worked out questions such as limited complex detection processes, poor sample detection limit or spending lots of time. Therefore, a method for detecting MiR-205 based on 2D COF nanosheets and fluorescent oligonucleotide probe was constructed and investigated in this study. The 2D COF nanosheet quenches the fluorescence of the fluorescent single-stranded DNA (ss-DNA) probes through fluorescence resonance energy transfer (FRET). The method enables to capture MiR-205 sensitively in aqueous solution with a detection limit of 4.78nM in the range 0–500nM and $R^2=0.989$, and the method offers great specificity in that it can distinguish the target miRNA from mismatch nontarget miRNAs. Considering its simple operability and excellent specificity, it has great application prospects in the detection of miRNA biomarker in clinical diagnosis and personalized treatment plan.

Cu–$X$ CNTs composites ($X=0$, 1, 2, 3 vol.%) were successfully prepared using a combination of pre-treatment, powder metallurgy and multi-directional forging processes, which provides a solution for the industrial manufacture of the composites with network CNTs structures. During the multi-directional forging process, the CNTs in the composites were distributed in a network under the synergy of metal flow and copper particle squeeze. Compared with other structure modes, the network CNTs can effectively carry and transfer loads resulting in the promotion of mechanical properties (such as, the tensile strength approximately 1.5 times higher than those of composites with the same volume fraction without network structure). The composite with 2 vol.% CNTs had the highest elongation in this experiment (41%), which is about 5 times higher than the composites with other CNTs distribution patterns. At a low CNTs content level (1vol.%), a complete load transfer network cannot be formed, resulting in a relatively insufficient mechanical properties of the composites. As the content level is exceeded (3vol.%), it caused significant agglomeration of the CNTs, which lead to fracture in the agglomerated CNTs and elongation degradation of the composites.

To use carbon nanotube fibers (CNT) extensively in a wide range of electrical and electronic applications, an essential key step is to produce a low-resistance, high-strength and reliable connection between the CNT fibers and other live parts in the circuit. In this study, meniscus-confined electrochemical deposition (ECD) process with silver was proven to be a practical way of joining CNT fibers together head-to-head. The whole ECD process was stable. The shape of the joints was found to depend on the shape of the tips of the CNT fibers. The deposited silver exhibited a dense and uniform microstructure and it was tightly bound to the CNT fibers, with a distinct interface between them. In the ECD process, the original morphology of the CNT network was maintained. The lowest electrical resistance of the CNT fibers joints was measured to be 8.72$\mathrm{\Omega }$, which is 45% lower than that of the original CNT fibers. The deposited joint sustained a fracture load of 7.5cN with an elongation of 0.4%.