Nano

We have prepared CoNPs@CN that cobalt nanoparticles(CoNPs) dispersed uniformly in the carbon matrix Composite (CN) via a facile and controllable method. Samples were characterized by X-ray diffraction (XRD), UV–V spectroscopy, scanning electron microscopy (SEM), high resolution transmission electron microscopy (HRTEM) and X-ray photoelectron spectroscopy (XPS). CoNPs@CN exhibited favorable photocatalytic activity under visible light irradiation. The results of quenching and photoluminescence experiments reveal the generation of main active species (•OH and •O${}_2^{-}$ radicals). The producing mechanism of active species can be attributed to that CoNPs@CN absorb photons and generate photogenerated electrons through localized surface plasmon resonance (LSPR) effect, then H₂O and O₂ in the solution react with the photogenerated hole and electrons to produce •OH and •O${}_2^{-}$ radicals.

Due to the various applications of nanocantilevers as nanosensors and nanoactuators in nanoelectromechanical systems, understanding their behavior is of particular importance. In operating environments, nanocantilevers are simultaneously exposed to mechanical forces and heat. This study aims to examine the behavior of an Euler–Bernoulli nanocantilever when it is placed under mechanical loads and exposed to heat at the same time. The effects of size, temperature, and force on the flexural behavior of the nanocantilever were investigated and the following characteristics were obtained via molecular dynamics simulation: nanocantilever displacement versus time, maximum bending, nanocantilever yielding time, and the minimum acceptable working frequency range for nanocantilever-based nanoswitches. It was found that applying forces greater than 0.00005eV/A, the studied nanocantilevers would rapidly undergo plastic deformation. For applied forces less than 0.00005eV/A, the nanocantilevers with length of 40nm, 30nm and 20nm can withstand upto 750K, 600K and 300K in 200ns to more than 1.5$\mu$s time period, respectively.

In this work, spherical Na(La,RE)(MoO${}_4{)}_2$ (RE = Eu/Yb-Er) double molybdates were prepared using the rare earth hydroxide (La,RE)(OH)SO₄ as a self-sacrificing template. The composition, structure, morphology, up/down conversion luminescence and fluorescence lifetime (FL) of the samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), fluorescence spectrophotometer, and Fourier transform infrared (FT-IR) spectrophotometer. The results indicate that highly pure spherical Na(La,RE)(MoO${}_4{)}_2$ (RE = Eu/Yb-Er) samples can be obtained from the proposed route. The room temperature and temperature-dependent up/down conversion luminescence properties of the resulting Na(La,RE)(MoO${}_4{)}_2$ (RE = Eu/Yb-Er) phosphors were analyzed in detail. The temperature-sensing performances for the two phosphors in both fluorescence intensity ratio (FIR) and FL modes were evaluated. Classical down and up-conversion photoluminescence (PL) from Eu${}^{3+}$ and Er${}^{3+}$ were observed. The down conversion phosphors were proved to be capable of sensing temperature via FL mode, and the maximum absolute sensitivity (S_A) and maximum relative sensitivity (S_R) were found to be $59\times 10^{-4}$K${}^{-1}$ (298K) and $52\times 10^{-4}$K${}^{-1}$ (523K), respectively. The up conversion phosphors Na(La,Yb,Er)(MoO${}_4{)}_2$ were well capable of sensing temperature via FIR mode through thermally coupled ²H${}_{11/2}$, ⁴S${}_{3/2}$ levels (I${}_{520}$/I${}_{551})$, and the maximum absolute sensitivity (S_A) and maximum relative sensitivity (S_R) were found to be $35\times 10^{-4}$K${}^{-1}$ (523K) and $115\times 10^{-4}$K${}^{-1}$ (348K), respectively.

Receptor-functionalized membranes provide a new paradigm for developing mechanical biosensors. However, the lower sensitivity of these biosensors is still a challenge. In this research, a sensitive and thin (1.5 $\mu$m) gold nanoparticles-polydimethylsiloxane (AuNPs-PDMS) membrane is fabricated by reducing HAuCl₄. Experimental results reveal that surface stress deforms the AuNPs-PDMS membrane, further increasing the resistance due to the tunneling mechanism and conductive percolation. During the functional process, the resistance change is consistent with theoretical prediction. The relative resistance change demonstrates a linear relationship with the glucose concentration. The biosensors exhibit a wider linear range for glucose from 0 to 30mM with a lower detection limit of 0.035mM. AuNPs-PDMS thin membrane-based surface stress biosensor shows promising application prospects to detect biomolecules.

Coupling low-temperature plasma technology with catalysts can significantly enhance air purification efficiency and mitigate the generation of secondary pollutants. In this study, mesoporous $\gamma$-Al₂O₃ supported Mn–Ce–Co ternary oxides were introduced into a widely employed tubular dielectric barrier discharges (DBD) reactor for indoor air purification. The plasma-catalytic degradation of HCHO exhibited the following degradation efficiency order: Mn–Ce–Co/$\gamma$-Al₂O₃ $>$ Mn/$\gamma$-Al₂O₃ $>$ Mn–Ce/$\gamma$-Al₂O₃ $>$ Co/$\gamma$-Al₂O₃ $>$ $\gamma$-Al₂O₃ $>$ Ce/$\gamma$-Al₂O₃ $>$ Plasma. When compared to plasma treatment alone, the catalyst resulted in a remarkable 1.8-fold enhancement under conditions of 3.0kV, $25^{\circ }$C, 60% RH. Additionally, the concentrations of the by-products O₃ and NO${}_x$ were significantly reduced by 88.2% and 93.3%, respectively. The synergistic interaction between Mn, Ce and Co oxides facilitated the formation and transportation of surface-reactive oxygen species, thereby contributing to the thorough oxidation of HCHO and organic intermediates during the plasma-catalytic process. Moreover, the high specific surface area offered by mesoporous materials enhanced the adsorption and catalytic activity towards HCHO.

The catalyst layer was introduced by a novel slurry impregnation process. In this process, phenolic resin, Ni particles and SiO₂ particles are acted as adhesives, catalysts and dispersants, respectively. CNFs which have a high length-diameter ratio were in situ grown on the surface of carbon fabrics via the CVD method. The microstructure, electrical conductivity, skin depth and electromagnetic interference shielding effectiveness (EMI SE) of CNFs/CF under different reaction times were investigated. The optimal process of CNFs/CF was obtained at 800${}^{\circ }$C for reacting 15min. In this condition, CNFs have a good graphitization degree and the diameter is around 25nm. Since the CNFs/CF composite possesses numerous channels, the electrical conductivity increases and the skin depth decreases. The electromagnetic (EM) waves could be trapped and attenuated, yielding outstanding EM shielding effectiveness. The total shielding effectiveness (SE${}_T)$ values were significantly under the ultrathin thickness. Consequently, the specific SE${}_T$ values of CNFs/CF reached 172.9 dB/cm, which means that the EM shielding effectiveness is excellent.

Amorphous Fe₂O₃ has special high electrochemical performance as anode materials of LIBs due to its disorderly arranged atoms. However, the issue of its low intrinsic electric conductivity should be solved rationally and facilely. In this work, amorphous Fe₂O₃ porous films are chemically deposited on the mechanically exfoliated multilayer graphene (MLG) nanosheets, forming a Fe₂O₃/MLG/Fe₂O₃ sandwich nanostructure. The addition of 10mg of EDTA-2Na is crucial for the formation of amorphous nature and holes in Fe₂O₃ films on MLG. This composite exhibits better electrochemical performance as LIB anodes than well-crystallized Fe₂O₃ nanoparticles, amorphous Fe₂O₃ films without holes and amorphous Fe₂O₃ isolated nanoparticles on MLG, which are prepared using 0mg, 5mg, 20mg of EDTA-2Na, respectively. The optimized composite delivers a reversible discharge capacity of 1067mAh g${}^{-1}$ at 100mA g${}^{-1}$ after 100 cycles. Moreover, a capacity of 522 mAh g${}^{-1}$ is delivered at a high current density of 2A g${}^{-1}$. The high electrochemical performance of the composite is attributed to the amorphous nature and porous film structure of Fe₂O₃, and well combination of Fe₂O₃ and highly conductive MLG substrate.