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Benefiting from the enhanced POD-like activity of Au/UiO-66, multi-target detection of glucose, dopamine and sulfide ion was realized based on a distinct mechanism.

A functionally graded Ni-Al coating can improve the hardness of low-carbon steel, which can then adapt to various conditions due to a high hardness. The primary purpose of this research was the preparation of a Ni-Al coating by adopting a two-step method including nickel plating and pack aluminizing. The coating phase and morphology were characterized with XRD, SEM and EDS. Subsequently, the hardness of the Ni-Al coating was measured using a nanoindentation test. The results show that different aluminum contents in the coating surface lead to different coating phases, mainly Ni2Al3. The change in the coating phases conformed to the Ni-Al binary phase diagram. The Ni-Al coating showed a continuous gradient structure and composition. In addition, the coating also showed continuous gradient variation, relating to the hardness.

Idiopathic pulmonary fibrosis is a chronic and highly lethal lung disease that largely associated with oxidative stress. Unfortunately, there is currently no effective antioxidant therapy targeting oxidative stress pathogenesis. One key and great challenge is finding ideal antioxidant materials with superior anti-fibrotic effects. In this study, we report novel antioxidant V4C3 nanosheets (V4C3 NSs) for treatment of pulmonary fibrosis by scavenging reactive oxygen and nitrogen species. It is found that the subtle auto-oxidation can adjust the valence composition of V4C3 NSs and prominently improve their antioxidant behavior. The valence engineering triggers the multiple antioxidant mechanisms of electron transfer, H atom transfer and enzyme like catalysis, thus endowing V4C3 NSs with broad-spectrum, high-efficiency and persistent antioxidant capacity. Benefiting from the super antioxidant properties and high biocompatibility, V4C3 NSs can significantly prevent myofibroblast proliferation and extracellular matrix abnormality, thus alleviating the progression of pulmonary fibrosis by ROS scavenging, anti-inflammation and rebuilding antioxidant defenses in the bleomycin-induced animal model. This study not only provides an important strategy for designing excellent antioxidant nanomaterials, but also proposes a nanoscheme for the treatment of pulmonary fibrosis and other oxidative stress-related diseases.

In this work, zeolitic imidazolate frameworks (ZIF-8) and carboxylated carbon nanotubes (CNTs) were compounded to prepare a kebab-like one-dimensional linear composite, ZIF-8@CNTs. The mixed-matrix membrane (MMM) for separating carbon dioxide is prepared by embedding it into the polymer matrix Pebax-1657. The results indicated the successful synthesis of the ZIF-8@CNT composite. The combination of ZIF-8 and carboxylated CNTs avoided the aggregation of ZIF-8 in the polymer, increased the free volume of the MMM, and enhanced the CO2 adsorption performance and CO2/N2 separation performance. In addition, the interaction between CNTs and ZIF-8 provided a fast transport channel for CO2 molecules and improved the mechanical properties of the MMM. The 5 wt % ZIF-8@CNT MMM showed the best separation performance with a CO2 permeability of 225.5 Barrer and a CO2/N2 selectivity of 48.9, which exceeded the Robeson upper limit in 2008. The combination of high permeability and selectivity made Pebax/ZIF-8@CNT MMMs promising for industrial CO2 separation applications.

Metal nanozymes hold promise for chemical and biological applications, and their implementation relies on high catalytic efficiency and stability. Using the metal-organic framework as an ideal carrier for well-dispersed ultra-small metal nanoparticles (NPs) is beneficial for improving the catalytic efficiency of nanozymes. In this study, a zirconium-based metal organic framework (UiO-66) with good chemical stability and high porosity was synthesized and used to construct Pt/UiO-66 nanocomposites. The percentage of Pt in UiO-66 can be tuned easily by adjusting the feeding amount of PtCl4 2-. Because of the confinement effect of mesopores, the Pt particles with an average diameter of 3.8 nm are formed and dispersed throughout the pores of the UiO-66 particle. The Pt/UiO-66 composites show efficient oxidase- and peroxidase-like activity. Both the oxidase- and peroxidase-like activities are dependent on the Pt percentage. Pt/UiO-66-6% exhibits enhanced peroxidase-like activity, ∼3.9 times higher than that of commercial Pt/C with 10 wt % Pt. We propose that the construction of Pt/UiO-66 increased the utilization efficiency and stability of Pt NPs and provided more active sites for catalytic reactions. Using the peroxidase-like activity of Pt/UiO-66, a colorimetric method that can be used for actual blood glucose detection was developed for the specific detection of glucose with a limit of detection of 0.033 mM.

The redox state disorder of biological system caused by oxidative stress can lead to a variety of clinical dysfunction and diseases. It is an important challenge to find artificial materials that can efficiently adjust the redox balance to maintain health. In this work, a nitrogen-doped carbon (NCDs) redox nanozyme loaded into metal organic framework (MOF, UiO-66) is designed to form NCDs/UiO-66 nanocomposites. The high specific surface area and porosity of UiO-66 serve as ideal carrier to support multifunctional NCDs. NCDs/UiO-66 nanocomposites are comprehensively investigated for their ability to scavenge or generate reactive oxygen species (ROS) and free radicals. Experimental results demonstrate that NCDs/UiO-66 can remove intrinsic free radicals (

A color tunable emission was obtained in CaHfO3:Ce3+,Tb3+ phosphor. XRD, luminescence spectra, decay curves, temperature-dependent emission spectra and quantum efficiency were used to characterize the structure and luminescence properties. Under 330 nm excitation, the Ce3+ singly doped CaHfO3 samples exhibited intense blue emission. The emission intensity reached the maximum at 1 mol% Ce3+. CaHfO3:0.1Ce3+ samples possessed high quantum efficiency of 52.05%. In Tb3+ co-doped CaHfO3:Ce3+ phosphors, the emission position of Ce3+ blue shifts slightly due to weaker crystal field strength around Ce3+. Besides, the energy transfer between Ce3+ and Tb3+ leads to tunable emission colors from blue to cyan, then to green. The energy transfer efficiency and thermal stability are investigated in detail.

The composition and structure of polyacrylonitrile (PAN) precursors play an important role during thermal stabilization, which influences the properties of the resulting carbon fibers. In this paper, PAN homopolymer and PAN-itaconic (IA) copolymers with different IA contents were synthesized by aqueous phase precipitation polymerization. The effects of IA content on the structure and thermal properties were studied using scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), differential scanning calorimetry (DSC), and thermogravimetric analysis (TGA). The morphology of PAN polymers showed that the average size of the PAN particles increased with the increase of IA content in the feed. The content of the IA comonomer on the copolymers was quantitatively characterized by the relative absorbance intensity (A1735/A2243) in FTIR spectrum. With the increase of IA content in the feed, PAN-IA copolymers exhibited lower degree of crystallinity and crystal size than the control PAN homopolymer. The results from DSC curves indicated that PAN-IA1.0 copolymers had lower initial exothermic temperature (192.4 &deg, C) and velocity of evolving heat (6.33 J g&minus, 1 &deg, C&minus, 1) in comparison with PAN homopolymer (Ti = 238.1 &deg, C and &Delta, H/&Delta, T = 34.6 J g&minus, 1) in an air atmosphere. TGA results suggested that PAN-IA1.0 copolymers had higher thermal stability than PAN homopolymer, which can form a ladder structure easier during thermal processing. Therefore, PAN-IA1.0 copolymers would be a suitable candidate for preparing high performance PAN based carbon fibers.

Polyacrylonitrile (PAN) grafted amino-functionalized multi walled carbon nanotubes (amino-MWCNTs) were synthesized by in situ polymerization under aqueous solvent. The grafted MWCNT/PAN nascent composite fibers were prepared by the wet spinning method. Fourier transform infrared spectroscopy and Raman spectroscopy indicated that the amino-MWCNTs and PAN macromolecular chains had interfacial interactions and formed chemical bonds. The grafting content of the PAN polymer on the amino-MWCNTs was up to 73.2% by thermo gravimetric analysis. The incorporation of the grafted MWCNTs improved the degree of crystallization and crystal size of PAN nascent fibers, and changed the thermal properties during exothermic processing in an air atmosphere. Morphology analysis and testing of mechanical properties showed that the grafted MWCNT/PAN nascent composite fibers with a more uniform diameter distribution and larger diameter had higher tensile strength and tensile modulus than the control PAN nascent fibers.

Nesting-site selection is an important aspect of the breeding process in birds, as it usually determines nesting and breeding successes. Many factors can affect bird nest-site selection, including anthropogenic disturbance. In an extreme desert environment, such as the Taklamakan Desert in China, birds’ survival pressure is high, especially for rare species such as the Xinjiang Ground-jay (Podoces biddulphi). We studied nest-site selection in this species from March 2017 to May 2019. A Chi-square test, independent sample t-test, Mann–Whitney U-test, and generalized linear models were applied to possible nest-site selection factors for Xinjiang Ground-jays. The main determining factors were the distances to human settlements, water, and the edge of the oasis. Xinjiang Ground-jays nested near available water resources for easier access, which is important in arid environments. Individuals chose to nest far from the oasis edges and settlements to increase food availability and reduce interference from human activities, respectively. Overall, water, food availability, and anthropogenic influence were the main factors affecting the nest-site selection of Xinjiang Ground-jays in this study. Therefore, these results suggest that there is a trade-off between survival and reproduction. Further studies are required to verify whether similar site preferences may also apply to other desert-dwelling species.

Development of high-performance electrocatalyst for oxygen reduction reaction is imperative to address the issues of energy and environment. Zeolitic imidazolate frameworks (ZIFs)/carbon nanotubes (CNTs) composites have been regarded as a promising precursor to fabricate efficient catalysts. However, it is challenging to synthesize ZIF/CNT composites with unique structure and controllable compositions. Herein, a CNT-directing assembly strategy is developed to synthesize ZIF/CNT nanonecklaces with unique structure and tunable Zn/Co ratios. The oxidized CNTs are employed as a structure-directing agent to prepare one-dimensional nanonecklaces. The ratios of Co/Zn in the ZIF can be adjusted from 0 to 8:2 by simply changing the amount of metal precursors. After carbonization and acid leaching, Co nanoparticles are embedded in the graphitization carbon matrix. Zn species are removed completely and produce plenty of nanopores in the carbon framework. Such ZIF/CNT nanonecklaces derived carbon composites are further used as a catalyst for oxygen reduction reaction, which show high onset potential (0.92 V) and high limiting current density (5.31 mA cm−2 at 0.30 V). This work provides a new synthesis strategy for the fabrication metal/carbon composited catalysts.

Y 2 O 3 :Eu 3+ nanophosphors were fabricated by direct thermal decomposition of monohydrate yttrium europium propionates, which can be facilely obtained via cocrystallization. The composition and structure of the cocrystallized product were confirmed by X-ray diffractionmetry (XRD), simultaneous differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) as well as inductively coupled plasma mass (ICP-MS) spectrometry. The effects of decomposition temperature on the resultant microstructures such as crystallinity, particle size and particle dispersibility were investigated by XRD and transmission electron microscopy (TEM). The dependence of their luminescent properties on decomposition temperature was also studied by fluorescence spectrophotometry. The results showed that the microstructures and luminescent intensities of Y 2 O 3 :Eu 3+ nanophosphors could be tuned by varying calcination temperatures of cocrystallized yttrium europium propionates from 600 to 1000 °C.

Nanocrystalline (La 1− x Eu x ) 2 Zr 2 O 7 series solid solutions were prepared by a simple and controllable salt-assisted combustion process. The samples were characterized by XRD, TEM and EDS. The results showed the partial substituted products were single-phase solid solutions. The effect of thermal treatment temperature on the crystal size of nanocrystals and the activation energy of crystal growth during calcinations were studied. And the activation energy of (La 1− x Eu x ) 2 Zr 2 O 7 series with x = 0.05, 0.1, 0.25, 0.5, and 0.75 was 25.4, 27.8, 28.0, 32.4, and 30.6 kJ/mol, respectively. TEM images revealed that the products were composed of well-dispersed cubic-like particles with the range of size at 20–50 nm. EDS results furtherly confirmed that the composition of the obtained compound was in agreement with the stiochiometric formular. The emission spectra of (La 1− x Eu x ) 2 Zr 2 O 7 nanocrystals at 385 nm upon excitation showed that there were some intense and prevailing emission peaks located at 590–650 nm.

Er2Sn2O7 nanocrystals were successfully synthesized by salt-assistant combustion method (SACM) at a relatively low temperature (600 °C). The Er2Sn2O7 nanocrystals were characterized by XRD, FT-IR, TEM and HRTEM. The effect of thermal treatment temperature on the crystal size of nanocrystals was studied and the activation energy of Er2Sn2O7 nanocrystals formation during calcination was calculated to be 88.1 kJ/mol. TEM results showed that the Er2Sn2O7 nanoparticles obtained by SACM were well-dispersed and uniform in particle size distribution. The interplanar distance of d222 measured from the HRTEM images was 0.301 nm, coinciding with the theoretical value.

Two lanthanide zirconates Ln2Zr2O7 (Ln = La and Nd) with pyrochlore structures were prepared by solid-state reaction at a relatively low temperature. The as-prepared Ln2Zr2O7 nanocrystals were characterized by XRD, FT-IR, TEM, HRTEM, EDS and BET. The as-obtained nanocrystals were composed of square-like particles with the average size of 20–50 nm. The interplanar distances of d222 and d440 measured from the HRTEM images for La2Zr2O7 nanocrystals were 0.303 nm and 0.185 nm, respectively, coinciding with the theoretical values. The interplanar distance of d222 for Nd2Zr2O7 was 0.307 nm. The La2Zr2O7 and Nd2Zr2O7 nanocrystals gave a relatively high value in surface area of 11.33 m2/g and 3.48 m2/g, respectively. Moreover, the photocatalytic activity was measured and the photodegraded amount of methyl orange catalyzed by La2Zr2O7 nanocrystals in 1 h was bigger than that of Nd2Zr2O7 nanocrystals.

Nanosized spinelCoAl2-xRexO4complex oxides were prepared by self-propagation combustion method. The products have been characterized by XRD, SEM, and EDS. The results indicated that Al3+can be partly replaced by Re3+when the doped amount is less than 10%, which forms single solid solution. The NIR reflectance and chromatic properties of samples have also been investigated. The substitution of Re3+for Al3+in CoAl2O4can increase the blueness of pigments. SEM results revealed that the obtainedCoAl2-xRexO4pigments consisted of highly dispersed spherical-like nanoparticles with uniform size distribution. EDS results indicated that the distribution of element was considerably uniform with no chemical segregation phenomenon.

The highly dispersed nanostructured NiTiO3pigments and NiTiO3/TiO2composite pigments can be synthesized at relative low temperature. The activation energy of crystal growth of NiTiO3during calcinations via salt-assistant combustion method is 9.35 kJ/mol. The UV-vis spectra results revealed that the absorbance decreased with the increasing of calcinations temperature due to small size effect of nanometer particles. The optical data of NiTiO3nanocrystals were analyzed at the near-absorption edge. SEM showed that the obtained NiTiO3nanocrystals and NiTiO3/TiO2nanocomposite were composed of highly dispersed spherical-like and spherical particles with uniform size distribution, respectively. The chromatic properties and diffuse reflectance of samples were investigated. The obtained NiTiO3/TiO2composite samples have higher NIR reflectance than NiTiO3pigments.

Well-dispersed nanocrystalline MnCr2O4was prepared by a salt-assisted combustion process using low-toxic glycine as fuel and Mn(NO3)2and Cr(NO3)3·9H2O as raw materials. The obtained products were characterized by X-ray Diffraction (XRD), Fourier Transform Infrared (FT-IR) spectroscopy, Raman spectroscopy, Transmission Electron Microscopy (TEM), and Scanning Electron Microscopy (SEM). The fabrication process was monitored by thermogravimetric and differential thermal analysis (TG-DTA). The phase formation process was detected by XRD, and MnCr2O4single phase with high crystallinity was formed at 700°C. TEM and SEM images revealed that the products were composed of well-dispersed octahedral nanocrystals with an average size of 80 nm. Inert salt-LiCl played an important role in breaking the network structure of agglomerated nanocrystallites.