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Antifouling coatings face some critical challenges toward applications, particularly poor mechanical properties, complex or expensive fabrication and non-transparency. This work reports a transparent fluorine-free antifouling coating with robust mechanical properties. Water and salt, alkali and acid solutions can slide off the coating surface (water contact angle > 105°) and remove dirt. The coating endows the substrate with remarkable protection against exposure to harsh chemical conditions, mechanical robustness against extensive abrasion and high hardness (6H–9H). The characteristics of this coating are derived from heavily cross-linking branched (3-aminopropyl)triethoxysilane with zirconium dioxide (ZrO2) ceramic nanoparticles by using a curing agent.

Tri-phase NiSe2/Ni2Co/CoSe2 heterostructures with graphitized carbon shells exhibit excellent cycling performance at high rates in Li–Se batteries.

The cascade Knoevenagel-hydrogenation reaction catalyzed by our smart Pickering nanoreactors can be carried out by a real one-pot method.

A 3D α-MoO3 nanostructure for high-performance triethylamine (TEA) detection was synthesized via the facial oxidation of MoS2 nanoflowers (NFs) obtained by a hydrothermal process. The influence of the time of hydrothermal process in growing MoS2 on the morphologies of the final MoO3 obtained after calcination was investigated. As-obtained MoO3 and their precursors were systematically characterized by various techniques, such as X-ray diffraction, Raman, scanning electron microscopy, transmission electron microscopy, X-ray photoelectron spectroscopy, and N2 adsorption–desorption isotherms. Results showed that MoO3 with a hierarchical layered nanostructure was successfully obtained. After hydrothermal treatment of the MoS2 precursor for 20 h, the typical MoO3-based sensor (called M20) exhibited a high response of 2.42 at a very low TEA concentration of only 0.1 ppm at 240 °C. The M20 sensor response to 50 ppm TEA was as high as 125 with a fast response/recovery time of 14/22 s. Moreover, the sensor had a high stability and reproducibility as well as a high selectivity against other interfering VOCs or gases. Due to the tendency of TEA to adsorb to active oxygen sites of MoO3, the enhanced sensing properties of MoO3 can be ascribed to the remarkable hierarchical structure and large surface area. MoO3 obtained after calcination of hydrothermally grown MoS2 is thus a promising sensing material for enhanced TEA gas detection.

Defect engineering is an important strategy to regulate electronic structure of electrocatalysts for electrochemical N2 fixation, aiming at improving the electron state density and enhancing the adsorption and activation of inert N2. In this paper, a high-temperature strategy to anneal the natural molybdenite under Ar atmosphere was developed, and the as-obtained molybdenite with S vacancies boosted a high activity for N2 reduction reaction. In 0.1 M HCl, the catalyst annealed at 800 °C exhibits a high Faradic efficiency of 17.9% and a NH3 yield of 23.38 μg h−1 mg-1cat. at −0.35 V versus reversible hydrogen electrode, two times higher than that of the pristine molybdenite. The facile one-step annealing method introduces the defects (e.g., S vacancies) in the surface of the natural molybdenite particles to prepare catalysts for generating ammonia by reducing nitrogen at room temperature under ordinary pressure, promoting the development of low-carbon economic prospect.

Due to the low solubility of BaF2, the BaTiF6:Mn4+ phosphor for whitelight-emitting diodes application has been generally synthesized by the hydrothermal route, during which process the valence of the manganese dopant is difficult to be controlled as tetravalent. In this paper, a new synthesis method that proceeded at room temperature was reported. This method uses BaTiOF4 as the precursor and allows for the control of the phase transformation rate from BaTiOF4 to BaTiF6 in the K2MnF6/HF acid solution. Benefitting from that, we successfully prepared red-emitting BaTiF6:Mn4+ elongated crystals with a single-crystal nature up to a record-breaking length of 200-300 μm. The effects of the crystallinity of the BaTiOF4 precursor on its phase transformation rate into BaTiF6 and on the optimal Mn4+ doping concentration were studied. The BaTiF6:Mn4+ single-crystal phosphor exhibits relatively excellent hydrolysis-resistant behavior after being immersed in water for 3 h, at which condition the commercial K2SiF6:Mn4+ has become brown. This study may inspire the room-temperature preparation of other hydrolysis-resistant alkali earth fluorotitanate or fluorosilicate phosphors with stable tetravalent manganese doping.

Background Alzheimer's disease (AD) is a neurodegenerative disease characterised with signature pathological lesions of extracellular senile plaques and intracellular neurofibrillary tangles comprising amyloid beta (Aβ) protein and hyperphosphorylated tau protein, respectively. Microglia, the major players of innate immune cells in the brain, can cleave Aβ via phagocytosis and autophagy. Methods To examine the effects of EGCG on the cognitive deficit of APP/PS1 mice, behavioural tests such as open-field test and Y-maze were performed and hippocampus tissues were collected for Immunofluorescence assay after EGCG treatment. We estimated expression levels of various related proteins by western blot to evaluate the role of EGCG in AD progression. To investigate whether EGCG protects SH-SY5Y cells following microglial cell-mediated clearance of Aβ1−42, we performed a co-culture experiment with SH-SY5Y cells and N9 microglia. Results Our results demonstrate that epigallocatechin-3-gallate (EGCG), a major green tea phytochemical, could improve the learning and memory abilities of AD mice, erase Aβ deposition, and promote microglial proliferation. The EGCG-induced Aβ clearance by microglia is mediated through the blockade of the histone deacetylase 6 (HDAC6), phosphoinositide 3-kinase (PI3K)/protein kinase B (AKT)/mammalian target of rapamycin (mTOR) pathway and the subsequent activation of autophagy. EGCG protects neuronal cells from Aβ1−42-mediated toxicity through the clearance of Aβ by microglia. Conclusion Our work describes an EGCG-HDAC6-PI3K/AKT/mTOR signalling axis that influences microglial autophagy, and suggests that the therapeutic targeting of this axis could enhance the cognitive function in AD by Aβ clearance.

Pickering emulsifiers are significant for organic reactions in an aqueous medium because they have the ability of emulsifying water-oil biphasic systems. For this reason, 2,5-bis[(E)-2-(triethoxysilyl)vinyl]pyridine [BTOSVP] containing a pyridine bridging group was selected as a precursor to prepare a novel salt of organosilicon framework (SOF), an amphiphilic mesoporous pyridine hydrobromide nanosphere. We first synthesized a mesoporous organosilicon framework made up of organic groups containing vinyl groups, pyridine groups, and so forth. Then, hydrobromic acid was added to protonate the pyridine groups in the mesoporous organosilicon framework. Eventually, pyridine hydrobromide salt was formed on the surfaces of channels, and the SOF was successfully prepared for the first time. Pyridine hydrobromide salt can be ionized in water into protonated pyridine cations located on the SOF surfaces and free Br-anions swimming around the protonated pyridine cations because of the electrostatic interaction. In the water-oil biphasic systems, hydrophilicity of SOF originates from the protonated pyridine cations and the lipophilicity of SOF comes from organic groups in the framework; thus, this new kind of SOF can be used as a new generation of solid Pickering emulsifiers. Most importantly, the mesoporous SOF nanosphere can also be used as a catalyst for significantly improved dibromination of olefins in an aqueous medium.

Lithium–sulfur batteries (LSBs) are a class of new-generation high-energy-density rechargeable batteries. However, the persisting issues of lithium polysulfide (LiPS) dissolution and shuttling severely impedes their practical applications. To address this challenge, we synthesized hierarchical porous carbon nanonet flakes (CNNFs) decorated with a small amount of loosely distributed MoS₂, as an effective interlayer for LiPSs stabilization. Due to the special hierarchical porous structures with large abundant micro-, meso-, and macro-pores derived from the linear-PEI-templated CNNFs and the chemisorption and electrocatalytic effects for MoS₂, the shuttling of the soluble polysulfides intermediates is efficiently alleviated, accompanied by a stabilized Li⁺ transportation pathway for the cell. A high initial capacity of 1413.8 mA h·g–¹ at 0.1 C and a stable capacity of 897.5 mA h·g–¹ at 0.5 C after 200 cycles are obtained, corresponding to a capacity decay rate of 0.063% per cycle. Moreover, after 500 cycles at 1 C, a discharging capacity of 515.7 mA h g–¹ with a Coulombic efficiency of 98.7% can be obtained. The trapping of polysulfides and the synergistic maintenance of electron and ion pathway can provide an effective stabilization strategy for high-performance lithium–sulfur battery.

Carbon-metal composites are promising multifunctional electrocatalysts, but it is still challenging to prepare carbon-metal composites with tunable structure and strong metal-carbon interactions. Here, we present a unique gas-foaming assembly strategy to prepare cytosine-Co chelate derived Co and N codoped carbon nanotube (Co-NCNT). The structure for Co-NCNTs could be easily controlled by regulating cytosine-Co coordination or the carbonization temperature. The optimal Co-NCNT possesses homogeneous distributed NCNTs (10 nm), CoOx (5 nm) and CoNx moieties to synergistically boost electrochemical processes, and offer mesoporous nanosheet architecture to guarantee fast mass migrate and electron transfer. As a result, Co-NCNT shows remarkable ORR performance (onset potential of 0.93 V in 0.1 M KOH electrolyte) along with significant OER and HER activity. More important, it was found that CoNx moieties are responsible for the remarkable electrocatalytic activity in Co-NCNTs, because CoNx could alter active center, enhance metal-carbon synergy, decrease interfacial resistance and reinforce the strength of composites. Therefore, this paper not just demonstrates an advanced multi-functional electrocatalyst, but could also give deep understanding on the designing of multifunctional electrocatalysts.

Lithium–selenium (Li–Se) batteries are considered a promising energy storage material due to their high electronic conductivity and volume capacity. However, the performance of Li–Se batteries is far away from commercial application, and few previous research studies achieved excellent performance of Li–Se batteries when the current density is higher than 5C (1C = 675 mA h g−1) to date. Recently non-noble metal single-atom catalysts have attracted extensive interest because of their low cost and maximum utilization, while introducing binuclear single atoms into Li–Se batteries is still a challenge. Herein, for the first time, a hierarchical porous carbon host with binuclear single-atom-sites FeN4 and Co2N3 with a PDA shell (APPC/Se@PDA) is prepared as the cathode for Li–Se batteries. The uniformly dispersed single-atom sites exhibit a synergistic effect by not only strengthening the binding force between C and Se species but also enhancing the transfer rate of electrons and Li+, which is demonstrated by electrochemical performance, ex situ X-ray photoelectron spectroscopy measurements and density functional theory (DFT) calculations. Moreover, the hierarchical pores and PDA shells provide physical confinement. As a result, APPC/Se@PDA exhibits a high specific capacity of 536 mA h g−1 at 0.2C after 220 cycles at a Se loading of 4 mg cm−2, and maintains a high reversible capacity of 645 mA h g−1 after 700 cycles at 2C with a low capacity attenuation of 0.0079% per cycle. Even at 10C and 23C, 420 mA h g−1 and 274 mA h g−1 are achieved after 1500 cycles and 2500 cycles, respectively. To the best of our knowledge, such an excellent performance at high current densities of Li–Se batteries has not been reported. Combining experiments and theoretical calculations, such a novel strategy broadens the future research of Li–Se batteries and further applications of non-noble metal single atoms.

Employing FeCl

Morphological control of covalent organic frameworks (COFs) is particularly interesting to boost their applications; however, it remains a grand challenge to prepare hollow structured COFs (HCOFs) with high crystallinity and uniform morphology. Herein, we report a versatile and efficient strategy of amorphous-to-crystalline transformation for the general and controllable fabrication of highly crystalline HCOFs. These HCOFs exhibited ultrahigh surface areas, radially oriented nanopore channels, quite uniform morphologies, and tunable particle sizes. Mechanistic studies revealed that H

Lithium-sulfur batteries, owing to the multi-electron participation in the redox reaction, possess enormous energy density, which has aroused much attention. Nevertheless, the detrimental shuttle effect, volume expansion, and electrical insulation of sulfur, have hindered their application. To improve the cyclability, a functional host, consisting of Co nanoparticles and N-doped hollow graphitized carbon (Co-NHGC) material, is elaborated, which has the advantages of: 1) the graphitized carbon material working as an electronic matrix to improve the utilization rate of sulfur; 2) the hollow structure relieving the stress change caused by volume expansion; 3) the rich active sites catalyze the electrochemical reaction of sulfur and entrap polysulfides. These advantages significantly improve the performance of the lithium-sulfur batteries. Accordingly, the S@Co-NHGC cathode exhibits excellent initial specific capacity, high coulombic efficiency, and excellent rate performance. This work utilizes a novel method of dopamine in situ etching of a metal-organic framework to synthetize the Co-NHGC host of sulfur, which will hopefully provide inspiration for other energy materials.

It is strongly desired to design and synthesize amphiphilic nanoreactors with tunable compatibility, which are stable at the biphasic interface in both acidic and alkaline environments. Herein, a novel amphiphilic R

Developing highly efficient, low-cost, and stable electrocatalyst for the oxygen evolution reaction (OER) is essential for hydrogen production by electrolyzing water. In this paper, ZnO/amorphous-FeOOH core-shell nanorod array is fabricated on Ni foil via a simple two-step chemical bath method and used as OER catalyst. Amorphous FeOOH possesses more O defects than crystalline FeOOH. Besides, the X-ray photoelectron spectroscopy (XPS) results reveal that the strong electron interactions on nano-interface between ZnO and FeOOH facilitate charge transfer from FeOOH to ZnO. Due to these advantages, the ZnO/amorphous-FeOOH hybrid nanorods exhibit excellent electrocatalytic performance for OER, with an overpotential of 301 mV at 10 mA cm−2, Tafel slope of 50 mV dec−1, and outstanding stability.

A precursor-engineering strategy coupled with a microwave molten-salt process (PE-MWMS) is developed to synthesize graphitic carbon nitride (g-C3 N4 ) with an isotype triazine/heptazine-based g-C3 N4 heterojunction as a photocatalyst for the hydrogen evolution reaction (HER) under visible light illumination. Four hybrid precursor combinations-thiourea/melamine, thiourea/dicyandiamide, urea/melamine, and urea/dicyandiamide-are used to synthesize g-C3 N4 heterojunctions by the PE-MWMS process. Control experiments indicate that the precursor components and microwave treatment have a great effect on the HER performance of the g-C3 N4 samples. Samples synthesized with the optimal molar ratios of thiourea/melamine (2:1), thiourea/dicyandiamide (2:1), urea/melamine (3:1), and urea/dicyandiamide (3:1), exhibit the highest HER rates of 3135, 2519, 2844, and 2565 μmol g-1 h-1 , respectively. The amounts of heptazine and triazine units in the g-C3 N4 samples can be easily adjusted by changing the ratios of the hybrid precursors and play a decisive role in improving the photocatalytic HER activity. Because of the unique composition and microstructure, the efficient separation of electron-hole pairs, the broadened photo-absorption edges, and the narrowed band gaps, the as-obtained triazine/heptazine-based g-C3 N4 nanostructures exhibit promising activity for HER application.

Blue light pumped red luminescence with broadband and high photon-energy emission is highly desired for phosphor-converted white light-emitting diodes (pc-wLEDs), to achieve a high color rendering index and high luminous efficacy. Mn4+-doped red-emitting phosphors generally exhibit sharp vibronic emissions associated with the parity- and spin-forbidden 2Eg→4A2g transitions. In this paper, two abnormal luminescence behaviors were observed for Mn4+ in the MgAl2O4:Mn4+ spinel phosphor with a short wavelength emission band peaking at 651 nm. Firstly, the Mn4+ 2Eg→4A2g transition exhibits ultrabroadband luminescence in MgAl2O4 and the large full-width at half-maximum (FWHM) is dependent both on the calcination temperature and on the partial substitution of Al3+ with Ga3+. Secondly, the thermal quenching behavior of the Mn4+ 2Eg→4A2g luminescence in MgAl2O4 shows a dependence on its thermal treatment and preparation method. The Rietveld refinement and Raman results demonstrate that the variation in the FWHM of the luminescence spectra is a sum effect of structural ordering (i.e., isotropic displacement decrease of constituent atoms) and the Mg ↔ Al anti-site disorder. A model for the observed varying thermal quenching of luminescence was tentatively proposed. The intrinsic thermal quenching temperature of Mn4+ luminescence in MgAl2O4 was found to be 390-400 K using the samples prepared by the co-precipitation and molten salt methods. The present work gives a novel perspective to understand the luminescence spectra of Mn4+ 2Eg→4A2g transition.

Building architectures to manipulate light propagation using a light-conversion matrix is one of the most competitive strategies to enhance photocatalytic performance. In this work, a bio-inspired SiO2 hard template with interconnected SiO2 with a one-dimensional structure was devised to enhance the visible light harvesting ability of g-C3N4, and the SiO2/g-C3N4 nanocomposite is cleverly synthesized via an in situ thermal polymerization method. Based on UV-vis diffuse reflectance spectrometry (UV-vis DRS) and finite difference time domain simulation (FDTD) measurements, it is found that the SiO2/g-C3N4 nanocomposite displays obviously enhanced visible light absorption and light-scattering when compared to pristine g-C3N4, suggesting it has highly enhanced light harvesting ability. As expected, SiO2/g-C3N4 displays a remarkable enhancement in photocatalytic H2 production when compared to bare g-C3N4. Such enhancement is attributed to the synergistic effect of g-C3N4 and SiO2 hard template microstructures. The SiO2 one-dimensional structure not only enhances light scattering to widen the visible-light absorption range and improve the utilization efficiency of solar energy, but it also increases the specific surface area of g-C3N4 by reducing its aperture size. This research has far-reaching implications for increasing the use of sunlight and improving the development of hydrogen energy.

Carbon nitride has become a focus of photocatalytic materials research in recent years, but the low specific surface area, the bad separation efficiency of photocarriers, poor quantum efficiency, terrible photocatalytic activity hinder the development of carbon nitride in the field of photocatalysis. The preparation of carbon nitride nanosheets is one of the effective methods to improve the photocatalytic efficiency of carbon nitride, but the traditional top-down stripping process is time-consuming, complicated and expensive. Here we report a simple, cheap, non-toxic and environmentally friendly bottom-up method to prepare a curled g-C3N4 nanosheet (NS-C3N4), which is performed at low temperature and normal pressure. In the aqueous solution, melamine and cyanuric acid are copolymerized to form a copolymer. Glycerol is inserted between the molecular layers of the prepolymer by thermal diffusion. Finally, high-quality and high-yield curled g-C3N4 nanosheets (NS-C3N4) are obtained by thermal peeling and polycondensation. The NS-C3N4 has an highly efficient photocatalytic hydrogen production of 4061.8 μmol h−1 g−1, and the hydrogen evolution activity is 37.5 times that of bulk-C3N4 (B-C3N4). The specific surface area of NS-C3N4 is 60.962 m2 g−1. UV-vis absorption spectra, steady-state and time-resolved photoluminescence, and photoelectrochemical tests were used to study its photocatalytic mechanism.