Photoinduced deformation behavior of poly(aryl ether)s with different azobenzene groups in the side chain.

Azobenzene-containing poly(aryl ether)s are a potential type of photoinduced deformable high-performance polymer. However, research on photoinduced deformation of azobenzene-containing poly(aryl ether)s focuses mainly on poly(aryl ether)s containing azobenzene groups in the main chain. In this paper, the photoinduced deformation of poly(aryl ether)s containing azobenzene groups in the side chain was studied for the first time. Two novel poly(aryl ether)s containing azobenzene groups in the side chain were synthesized, and their photoinduced isomerization behavior and photoinduced deformation behavior were studied. It could be seen that the match of the excitation luminescence to the maximum absorption peak of the azobenzene groups was more compatible, and the photoinduced motion of the polymers was faster. In addition, poly(aryl ether)s containing azobenzene groups in the side chain showed highly stable photoinduced deformation. The results of this work will be helpful for designing polymers which could be controlled by lasers of different wavelengths.

Photocorrosion-Based BiOCl Photothermal Materials for Synergistic Solar-Driven Desalination and Photoelectrochemistry Energy Storage and Release.

Solar-driven interfacial evaporation is one of the most promising desalination technologies. However, few studies have effectively combined energy storage with evaporation processes. Here, a novel multifunctional interfacial evaporator, calcium alginate hydrogel/bismuth oxychloride/carbon black (HBiC), is designed, which integrates the characteristics of interfacial evaporation and direct photoelectric conversion. Under illumination, the Bi nanoparticles which were produced by photoetching of BiOCl and its reaction heat are simultaneously used for the heating of water molecules. Meanwhile, part of the solar energy is converted into chemical energy through the photocorrosion reaction and stored in HBiC. At night, Bi NPs undergo autooxidation reaction and an electric current is generated during this process (like a metal-air battery), in which the maximum current density is more than 15 µA cm-2. This scientific design cleverly combines desalination with power generation and provides a new development direction for energy collection and storage.

Asymmetric ultrathin silica nanonets as a super-performance emulsifier.

HYPOTHESIS: Pickering emulsions have been used in many fields such as catalytic synthesis, pharmaceutics and oilfield chemicals. They usually have good stability, but in some extreme conditions such as at high temperatures or in special liquid-liquid systems, poor stability is often encountered. EXPERIMENTS: Herein, ultrathin silica nanosheets with controllable morphologies were synthesized via a simple interfacial anisotropic self-assembly approach integrated with pore-forming techniques. By regulating the size, density and pattern of the apertures, three types of unique nanosheets including mesoporous nanosheets, meso/macroporous topology-nanosheets and asymmetric nanonets with hollows were obtained. FINDINGS: After a simple hydrophobic modification, the nanonets exhibited super-performance as particulate emulsifiers, owing to their two-dimensional (2D) structures of large pore volume and hierarchical pore/hollow arrangements. As a result, those silica nanonets can stabilize various emulsion systems at considerably high temperatures that are difficult to be stabilized by conventional particulate emulsifiers even at a dose of 100x higher. This work paves a promising way to develop novel 2D asymmetric nanomaterials with tunable compositions, aperture parameters and morphologies for emulsification and potential applications.

Preparation of asymmetric particles by controlling the phase separation of seeded emulsion polymerization with ethanol/water mixture.

Alcohols are discovered for the first time to tune the morphology of poly(vinyl benzyl chloride)-poly(3-methacryloxypropyltrimethoxysilane) (PVBC-PMPS) composite particles through seeded emulsion polymerization within the alcohol/water mixture. Here, monodispersed linear PVBC particles was synthesized through the dispersion polymerization and employed as the seeds. The as-obtained PVBC-PMPS composite particles could be dramatically tuned from core-shell structures to snowman-like particles, to dumbbell-shaped particles, to inverse snowman-like particles when the ethanol content in reaction mixtures is only adjusted within a narrow range. The morphology of fresh PMPS bulges was observed after removing the linear PVBC seeds with N,N'-dimethyl formamide, and their formation mechanism was studied by monitoring the free radical polymerization and sol-gel process of 3-methacryloxypropyltrimethoxysilane. It has been confirmed that the sol-gel kinetics were the main factor on the particles' morphology. In addition, morphologies of PVBC-PMPS particles were also varied by the MPS feeding amount, types of the co-solvent and pH values of alcohol/water mixtures.

Chemical coupling of manganese-cobalt oxide and oxidized multi-walled carbon nanotubes for enhanced lithium storage.

Carbonaceous materials are extensively utilized to optimize the electrochemical performance of the transition metal oxides as anode for lithium-ion batteries. However, the in-depth mechanism of the synergistic effect and the interfacial interaction between transition metal oxides and conductive carbon material has not been elucidated clearly. Herein, by using the oxidized multi-walled carbon nanotubes (oMWCNTs), an advanced MnO2/(Co, Mn)(Co, Mn)2O4/oMWCNTs (MO/CMO/oMWCNTs) nanocomposite with abundant metal-oxygen-carbon (Me-OC) bonds as linkage bridge is fabricated for the first time. The strong covalent bonds interactions can simultaneously enhance the intrinsic sluggish kinetics and structural stability of MO/CMO/oMWCNTs nanocomposite. Meanwhile, the mixed transition metal oxides featuring mix valence state can significantly promote the electrode material activity. Consequently, the newly prepared MO/CMO/oMWCNTs electrode displays superior long-term durability with the capacity of 897 mAh g-1 over 1000 cycles at 2 A g-1 and ultrafast charging/discharging capability of 673 mAh g-1 at 5 A g-1. Detailed electrochemical kinetic analysis reveals that over 70% of the energy storage of MO/CMO/oMWCNTs electrode is dominated by the pseudocapacitive behavior. This work demonstrates an easily scalable approach for constructing high-performance transition metal oxides/carbon electrode materials through interfacial regulation.

A sensitive cholesterol electrochemical biosensor based on biomimetic cerasome and graphene quantum dots.

A simple and sensitive electrochemical cholesterol biosensor was fabricated based on ceramic-coated liposome (cerasome) and graphene quantum dots (GQDs) with good conductivity. The cerasome consists of a lipid-bilayer membrane and a ceramic surface as a soft biomimetic interface, and the mild layer-by-layer self-assembled method as the immobilization strategy on the surface of the modified electrode was used, which can provide good biocompatibility to maintain the biological activity of cholesterol oxidase (ChOx). The GQDs promoted electron transport between the enzyme and the electrode more effectively. The structure of the cerasome-forming lipid was characterized by Fourier transform infrared (FT-IR). The morphology and characteristics of the cerasome and GQDs were characterized by transmission electron microscopy (TEM), zeta potential, photoluminescence spectra (PL), etc. The proposed biosensors revealed excellent catalytic performance to cholesterol with a linear concentration range of 16.0 × 10-6-6.186 × 10-3 mol/L, with a low detection limit (LOD) of 5.0 × 10-6 mol/L. The Michaelis-Menten constant (Km) of ChOx was 5.46 mmol/L, indicating that the immobilized ChOx on the PEI/GQDs/PEI/cerasome-modified electrode has a good affinity to cholesterol. Moreover, the as-fabricated electrochemical biosensor exhibited good stability, anti-interference ability, and practical application for cholesterol detection.

A Dual Photoelectrode Photoassisted Fe-Air Battery: The Photo-Electrocatalysis Mechanism Accounting for the Improved Oxygen Evolution Reaction and Oxygen Reduction Reaction of Air Electrodes.

Effective utilization of solar energy in battery systems is a promising solution to achieve sustainable and green development. In this work, a photoassisted Fe-air battery (PFAB) with two photoelectrodes of ZnO-TiO2 heterostructure and polyterthiophene (pTTh)-coated CuO (pTTh-CuO) grown on fluorine-doped tin oxide (FTO) is proposed. The band structure of semiconductors and the charge-transfer mechanism of heterostructure are studied. The electrochemical results show that the photogenerated electrons and holes play key roles in reducing the oxygen evolution reaction (OER)/oxygen reduction reaction (ORR) overpotential in the discharging and charging processes, respectively. The short-circuit current density, the open-circuit voltage, and the maximum power output of the PFAB can reach 34.28 mA cm-2 , 1.15 V, and 5.69 mW cm-2 upon illumination, respectively. The photoassisted Fe-air battery exhibits a low charge voltage of 0.64 V for ZnO-TiO2 as photoelectrode and a discharge voltage of 1.38 V for pTTh-CuO as a photoelectrode at 0.1 mA cm-2 .

Smart Solar-Metal-Air Batteries Based on BiOCl Photocorrosion for Monolithic Solar Energy Conversion and Storage.

Herein, a BiOCl hydrogel film electrode featuring excellent photocorrosion and regeneration properties acts as the anode to construct a novel type of smart solar-metal-air batteries (SMABs), which combines the characteristics of solar cells (direct photovoltaic conversion) and metal-air batteries (electric energy storage and release interacting with atmosphere). The cyclic photocorrosion processes between BiOCl (Bi3+ ) and Bi can simply be achieved by solar light illumination and standing in the dark. Upon illumination, the device takes open-circuit configuration to charge itself from the sunlight. Notably, in this system, the converted solar energy can be stored in the SMABs without the need of external assistance. In the discharging process in the dark, Bi0 spontaneously turns back to Bi3+ producing electrons to induce the oxygen reduction reaction. With an illumination of 15 min, the battery with an electrode area of 1 cm2 can be continuously discharged for ≈3000 s. Taking elemental Bi as the calculation object, the theoretical capacity of the SMABs is 384.75 mAh g-1 , showing its potential application in energy storage. This novel type of SMABs is developed based on the unique photocorrosive and self-oxidation reaction of BiOCl to achieve photochemical energy generation and storage.

Synergy of Bi2 O3 and RuO2 Nanocatalysts for Low-Overpotential and Wide pH-Window Electrochemical Ammonia Synthesis.

Electrocatalytic nitrogen reduction reaction (NRR) under ambient conditions is still seriously impeded by the inferior NH3 yield and low Faradaic efficiency, especially at low overpotentials. Herein, we report the synthesis of nano-sized RuO2 and Bi2 O3 particles grown on functionalized exfoliated graphene (FEG) through in situ electrodeposition, denoted as RuO2 -Bi2 O3 /FEG. The prepared self-supporting RuO2 -Bi2 O3 /FEG hybrid with a Bi mass loading of 0.70 wt% and Ru mass loading of 0.04 wt% shows excellent NRR performance at low overpotentials in acidic, neutral and alkaline electrolytes. It achieves a large NH3 yield of 4.58±0.16 µgNH3 h-1  cm-2 with a high Faradaic efficiency of 14.6 % at -0.2 V versus reversible hydrogen electrode in 0.1 M Na2 SO4 electrolyte. This performance benefits from the synergistic effect between Bi2 O3 and RuO2 which respectively have a fairly strong interaction of Bi 6p orbitals with the N 2p band and abundant supply of *H, as well as the binder-free characteristic and the convenient electron transfer via graphene nanosheets. This work highlights a new electrocatalyst design strategy that combines transition and main-group metal elements, which may provide some inspirations for designing low-cost and high-performance NRR electrocatalysts in the future.

Superhydrophobic Coating Derived from the Spontaneous Orientation of Janus Particles.

A superhydrophobic surface was achieved using a monolayer of the perpendicularly oriented epoxy-silica@polydivinylbenzene (PDVB) Janus particles (JPs) on an epoxy resin substrate. The epoxy-silica@PDVB JPs were synthesized from the silica@PDVB/polystyrene (PS) JPs through selective etching of the PDVB/PS belly and the surface modification of the silica part. The modified silica parts can be covalently bonded with the epoxy resin to make the perpendicular orientation spontaneous as well as the coating more robust. The outward PDVB bellies can constitute the micro-/nanoscale hierarchical structures for the superhydrophobic property. The superhydrophobic coating exhibits water repellence and self-cleaning properties. Moreover, the coating exhibits good chemical durability that it can keep the superhydrophobic property after long-time immersion in various aqueous solutions and organic solvents. The coating is still superhydrophobic after water flushing and mechanical wearing, showing the perfect mechanical durability.

Pickering emulsion-embedded hierarchical solid-liquid hydrogel spheres for static and flow photocatalysis.

Pickering emulsion-based photocatalysis is considered to be a promising system due to its large active surface area and water/oil spatial separation capability for enrichment of substrates and products. In this work, a novel hierarchical structure composed of calcium alginate gel sphere wrapped ionic liquid-in-water Pickering emulsion with TiO2 in the water phase, which are stabilized by graphene oxide, is prepared via a facile one-step emulsion gelation method. Such subtle combination of Pickering emulsion, hydrogel and TiO2 with a multi-stage solid-liquid assemblage structure shows enhanced degradation activity of 2-naphthol into small molecular alkanes under simulated solar irradiation. The photodegradation activity is attributed to the ionic liquid as adsorption medium for 2-naphthol, and the high-efficient charge separation at graphene oxide/TiO2 interface superior to that of pure TiO2. More importantly, the as-prepared millimeter-sized assembled gel spheres can be directly used as the column filler to construct continuous flow photocatalytic system, maintaining the promising performance in removing pollutants from water with ~100% remove ability of 2-naphthol on stream. A charge transfer mechanism of the photocatalyst is proposed, i.e. photogenerated charges are separated in TiO2/graphene oxide p-n heterostructure at the interface of Pickering emulsion droplets.

Carbon Dots as an Indicator of Acid-Base Titration and a Fluorescent Probe for Endoplasm Reticulum Imaging.

In this study, carbon dots (CDs) with red color are successfully prepared via hydrothermal treatment of o-phenylenediamine and urea. The as-prepared red CDs exhibit an acidichromism feature, making them turn purple at pH 4.4 and become blue at pH 3.3. Further investigations reveal that the surface chemical bond species of CDs are responsible for the acidichromism feature. Taking advantage of the acidichromism feature, the CDs are employed as a titration indicator for analysis of alkali samples, which gives rise to satisfactory results without significant difference between the titration methods using CDs and methyl orange or a mixture of methyl red and bromocresol green as indicators. The CDs show excitation-independent fluorescence with dual-emission at 600 and 650 nm, along with a respectable quantum yield of 20.1%, which provides the CDs with deep tissue penetration and minimum autofluorescence background that is desirable in bioimaging. In addition, the CDs are found to light up endoplasm reticulum particularly, indicating their endoplasm reticulum targeting capability, which is proven by a colocalization study with other classical subcellular dyes. Endocytosis inhibiting investigations confirm that the endoplasm reticulum targeting ability is mainly attributed to the caveolin/lipid-raft-mediated endocytosis pathways of CDs. This study not only presents a facile approach for red CDs but also explores the possibility of CDs in titration analysis and in endoplasm reticulum targeting imaging.

Ultrathin 1T-MoS2 Nanoplates Induced by Quaternary Ammonium-Type Ionic Liquids on Polypyrrole/Graphene Oxide Nanosheets and Its Irreversible Crystal Phase Transition During Electrocatalytic Nitrogen Reduction.

Ultrathin nanoplates of metastable 1T-MoS2 have been successfully stabilized and uniformly distributed on the surface of n-butyl triethyl ammonium bromide functionalized polypyrrole/graphene oxide (BTAB/PPy/GO) by a very simple hydrothermal method. BTAB as a typical kind of quaternary ammonium-type ionic liquids (ILs) played a crucial role in the formation of the obtained 1T-MoS2/BTAB/PPy/GO. It was covalently linked with PPy/GO and arranged in a highly ordered order at the solid-liquid interface of PPy/GO and H2O due to Coulombic interactions and other intermolecular interactions, which would induce and stabilize ultrathin 1T-MoS2 nanoplates by morphosynthesis. The good electrocatalytic activity toward nitrogen reduction reaction (NRR) with strong durability and good stability can be achieved by 1T-MoS2/BTAB/PPy/GO due to their excellent inorganic/organic hierarchical lamellar micro-/nanostructures. Especially, after the long-term electrocatalysis for NRR at a negative potential, metastable 1T-MoS2 as the catalytic center undergoes two types of irreversible crystal phase transition, which was converted to 1T'-MoS2 and Mo2N, caused by the competitive hydrogen evolution reaction (HER) process and the electrochemical reaction between the electroactive 1T-MoS2 and N2, respectively. The new N-Mo bonding prevents Mo atoms from binding to other N atoms in N2, resulting in the deactivation of the electrocatalysts to NRR after being used for 18 h. Even so, quaternary ammonium-type ILs would induce the crystal structures of transition-metal dichalcogenides (TMDCs), which might provide a new thought for the reasonable design of electrocatalysts based on TMDCs for electrocatalysis.

Bismuth-Based Free-Standing Electrodes for Ambient-Condition Ammonia Production in Neutral Media.

Electrocatalytic nitrogen reduction reaction is a carbon-free and energy-saving strategy for efficient synthesis of ammonia under ambient conditions. Here, we report the synthesis of nanosized Bi2O3 particles grown on functionalized exfoliated graphene (Bi2O3/FEG) via a facile electrochemical deposition method. The obtained free-standing Bi2O3/FEG achieves a high Faradaic efficiency of 11.2% and a large NH3 yield of 4.21 ± 0.14 [Formula: see text] h-1 cm-2 at - 0.5 V versus reversible hydrogen electrode in 0.1 M Na2SO4, better than that in the strong acidic and basic media. Benefiting from its strong interaction of Bi 6p band with the N 2p orbitals, binder-free characteristic, and facile electron transfer, Bi2O3/FEG achieves superior catalytic performance and excellent long-term stability as compared with most of the previous reported catalysts. This study is significant to design low-cost, high-efficient Bi-based electrocatalysts for electrochemical ammonia synthesis.

Surface modification of cerasomes with AuNPs@poly(ionic liquid)s for an enhanced stereo biomimetic membrane electrochemical platform.

A novel liposomal nanocomposite, Au@PIL-cerasome, with biocompatibility and conductivity was fabricated via the self-assembly of cerasomes and gold nanoparticles (AuNPs) stabilized by poly(ionic liquid)s (PILs). The surface charge, morphology and chemical composition of the nanocomposites were characterized by the zeta potential, UV-vis, TEM, SEM and EDS. The nanocomposites exhibited structural stability directly on the surface of solid electrodes, without fusion. Electrochemical impedance experiments demonstrated that the nanocomposites had an enhanced conductivity compared with unmodified cerasomes. Horseradish peroxidase (HRP), as a reporter, was immobilized on the nanocomposites without denaturation or inactivation. The direct electron transfer of HRP was achieved, and the HRP/Au@PIL-cerasome/GCE exhibited an amplified current and improved electrocatalytic activity. Activity towards H2O2 displayed a linear range over 10-70 µM and a detection limit of 3.3 µM. Activity towards NO2- displayed linear ranges over 1-5 mM and 5-1280 mM, and the limit of detection was 0.11 mM. In addition, the electrode was stable and reproducible, with 6% RSD. Such multi-component liposomal nanocomposites with an enhanced electrical performance pave a better way for building novel and straightforward 3D stereo biomimetic electrochemical platforms and even molecular communication systems to investigate information transduction between cells.

Bi-continuous emulsion using Janus particles.

Bi-continuous emulsion stabilized with amphiphilic Janus particles was achieved. Phase inversion of the as-formed emulsion was driven by increasing water content. The orientated Janus particle monolayer at the bi-continuous emulsion interface is interconnected by interfacial polymerization to form robust materials with amphiphilic channels.

Ultrathin NiS/Ni(OH)2 Nanosheets Filled within Ammonium Polyacrylate-Functionalized Polypyrrole Nanotubes as an Unique Nanoconfined System for Nonenzymatic Glucose Sensors.

Ultrathin two-dimensional NiS/Ni(OH)2 nanosheets (NiS/Ni(OH)2 NSs) were successfully filled within the hollow interiors of ammonium polyacrylate-functionalized polypyrrole nanotubes (NH4PA/PPyNTs) by a simple solvothermal method. This kind of novel hierarchical nanostructures with typical structural features of a nanoconfined system, denoted by NiS/Ni(OH)2/NH4PA/PPyNTs, were prepared by two main sections: polyacrylic acid (PAA) was first polymerized on PPyNTs containing vinyl groups, and the obtained PAA/PPyNTs exhibited a typical Janus structure, whose external surface was covered with carboxyl groups and the internal surface was still covered with PPy chains; second, Ni2+ ions as a precursor were facilely combined with -NH- segments in PPy chains by the coordination interaction under the solvothermal environment; therefore, NiS/Ni(OH)2 NSs (<1 nm) were well distributed on the internal surface of NH4PA/PPyNTs by the in situ growth. Because of the synergistic effects of ionizable NH4PA, PPy with good conductivity, NiS and Ni(OH)2 with electrocatalytical activity, as well as the nanoconfinement effect, the obtained NiS/Ni(OH)2@NH4PA/PPyNTs exhibited excellent electrocatalytic performance for detecting glucose. Sufficiently thin shells composed of ionizable NH4PA and good conductive PPyNTs can not only promote the electronic transmission effectively during the electrochemical detection of glucose but also hardly limit the transport of glucose and products. In addition, ultrathin NiS/Ni(OH)2 NSs may further enhance the electrocatalytic performance for glucose because of the more exposed active sites with the large surface area. Therefore, NiS/Ni(OH)2@NH4PA/PPyNTs can be applied as a good electrode material with stability and sensitivity for building a nonenzymatic glucose sensor.

Magnetic-Responsive Janus Nanosheets with Catalytic Properties.

In this article, we describe a method to fabricate magnetic-responsive Janus nanosheets with catalytic properties via the surface protection method. Fe3O4 nanoparticles and PW12O403--based ionic liquid are located on the two opposite sides of the Janus nanosheets, respectively. The Janus nanosheets are characterized by Fourier transform infrared, scanning electron microscopy, transmission electron microscopy, atomic force microscopy, and ζ-potential analyses. They are used as recyclable catalysts to the esterification reaction of methanol and oleic acid for their magnetic-responsive and catalytic properties. The esterification ratio is up to 80% and there is nearly no change when Fe3O4 nanoparticles/PW12O403--based ionic liquid composite nanosheets were recycled four times.

Construction of multifunctional electrochemical sensor based on electroactivity-adjustable poly (ionic liquids)/reduced graphene oxide.

In this article, a novel electroactivity-adjustable poly (ionic liquids)/reduced graphene oxide (PIL-GP) was developed and utilized for the fabrication of multifunctional, high stable electrochemical sensors. The structure, morphology and surface charge properties of PIL-GP have been systematically studied. And the selective detection performance of dopamine (DA) on PIL-GP modified glassy carbon electrode (GCE) were further explored by cyclic voltammetry (CV) and differential pulse voltammetry (DPV). More importantly, by virtue of the anion exchange property of PIL, electroactive Fe(CN)63-/PIL-GP/GCE and Polyoxometalates (PWA)/PIL-GP/GCE were easily fabricated and their electrochemical detection performance of ascorbic acid (AA) and bromate were investigated respectively. The results showed that PIL-GP/GCE based electrochemical sensors provided higher sensitivity, lower detection limits and outstanding anti-interference ability in certain detection system. It was indicated that this general approach to construct electroactivity-adjustable sensors with various electroactive anions possessed a broad application prospect.

The ultrasound thermal cracking for the tar-sand bitumen.

The influence of ultrasonic irradiation on the tar-sand bitumen in the process of thermal cracking with an inert atmosphere was investigated thoroughly. The product distribution and coke characteristic produced by the conventional thermal cracking (CTC) and ultrasound thermal cracking (UTC) were invested at the following condition: ultrasound frequency 20 kHz, ultrasonic power 2000 W, reaction time 2 h, reaction temperature from 400 to 440 °C. The result of the liquid products distribution indicated that UTC can significantly increase gasoline yield and diesel yield, and dramatically reduce VGO (Vacuum Gas Oil) yield and residuum (greater than 500 °C) yield. The analysis of gas products showed that there were no significant differences for the gas distribution between the two reactions (methods), indicating that reaction of UTC still conformed to a radical chain mechanism, but the ratio of olefin/paraffin was greatly reduced in the process of UTC, which was attributed to the hydrogen transfer reaction promoted by ultrasound. The result of the analysis by SEM, FT-IR, Raman, XRD and Zeta potential demonstrated that there was a significant difference for the morphology of cokes produced by the two methods. Mesocarbon microbeads (MCMB) was discovered in the process of UTC, which should be due to that the polymerization of the free macro-radicals produced from PAHs (Polycyclic Aromatic Hydrocarbons) promoted by ultrasonic cavitation. In addition, it can be inferred that the viscosity of the second liquid phase was reduced by ultrasonic mechanical function through the breakage of the stack of asphaltene molecules cross-linked by van der Waals force. According to the mesophase theory, the ultrasound irradiation promoted the formation of the second liquid phase, extended its existence time and reduced its viscosity, resulting in the formation of MCMB controlled by the surface tension during the process of UTC.