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CuO supported catalyst with high valence rhenium doping were specially studied for photoelectrocatalytic reduction of CO2 to small molecular alcohols, which were synthesized by nitrate thermal decomposition method on anatase TiO2 nanotube arrays (TiO2-NTs). Photoelectrochemical measurements indicate that the high valence rhenium doping helps in improving the catalytic activity and selectivity of CuO supported catalysts. For the case of 6 wt% Re-doped CuO/TiO2-NTs calcined at 723 K, the principal products are methanol and ethanol with yield up to 19.9 μmol and 7.5 μmol after 5 h photoelectrocatalysis at external potential of −0.4 V under simulated solar illumination. In contrast, the products catalyzed by undoped CuO/TiO2-NTs are only methanol and formaldehyde. These results indicate that the high valence rhenium doping will promote the alcoholization process and benefit the C C coupling, leading to the selective conversion of CO2 to ethanol. Furthermore, under suitable external potential (-0.5 V) the CO2 conversion product is almost entirely composed of ethanol.

Developing an oxygen evolution reaction electrocatalyst with low cost, abundant reserves and excellent performance is essential for the large scale application of renewable hydrogen energy. Herein, a selenium doped hierarchical Ni-based electrocatalyst was fabricated. Nickel nanosheet array (NNA) was firstly electrodeposited on stainless steel, and then selenium was doped in the NNA to form a hierarchical nanosheet structure via a hydrothermal process. The effect of hydrothermal temperature and duration on the OER performance were investigated. Results shown that after selenization at 140 °C for 12 h, the NNA electrodeposited for 30 min performed best OER performance with a current density of 50 mA cm−2 at overpotential of 365 mV and a small Tafel slope of about 34 mV dec−1. This work provides a valuable strategy to design high efficiency electrocatalysts and shows the universality of selenization for improving catalytic performance.

Single-crystal cathode materials for lithium-ion batteries have attracted increasing interest in providing greater capacity retention than their polycrystalline counterparts. However, after being cycled at high voltages, these single-crystal materials exhibit severe structural instability and capacity fade. Understanding how the surface structural changes determine the performance degradation over cycling is crucial, but remains elusive. Here, we investigate the correlation of the surface structure, internal strain, and capacity deterioration by using operando X-ray spectroscopy imaging and nano-tomography. We directly observe a close correlation between surface chemistry and phase distribution from homogeneity to heterogeneity, which induces heterogeneous internal strain within the particle and the resulting structural/performance degradation during cycling. We also discover that surface chemistry can significantly enhance the cyclic performance. Our modified process effectively regulates the performance fade issue of single-crystal cathode and provides new insights for improved design of high-capacity battery materials., Performance improvement of cathode materials represents one of the most critical technological challenges for lithium-ion batteries. Here the authors show a close correlation between surface chemistry and phase distribution from homogeneity to heterogeneity, and its impact on the cyclic performance.

In this study, carbon aerogel (CA) were obtained by inexpensive bacterial cellulose (BC) hydrogel freeze-dried and carbonized under N2 atmosphere. Then nickel sulfide (NiS)/CA composite aerogel electrodes with different contents were successfully prepared by a one-step solvothermal method. The morphology, phases and surface electronic state of these electrodes were characterized by SEM/TEM, XRD and XPS, respectively, and their electrocatalytical properties for methanol oxidation were investigated by cyclic voltammetry (CV) in the alkaline media of methanol. The NiS particles dispersed uniformly on CA, and the obtained material maintained the reticulated porous structure of BC. The methanol oxidation peak current density of CNS-0.5 at 0.8 V reached 43 mA/cm2 (263 mA/mg). After 1000 cycles, the peak current density retained 92% of the initial state. The composite electrode has good catalytic activity and good cycle performance for methanol catalysis. Nickel sulfide with high crystallinity transforms to nickel oxide with low crystallinity after a long cycle test, which results in excellent cycle performance of the composite. NiS/CA electrodes have the potential for application in portable or wearable devices.

Herein, we report a simple approach to synthesize CuFeO2/TNNTs photocathodes composed of high-temperature resistance n-type Nb-doped TiO2 nanotube arrays (TNNTs) and p-type CuFeO2 for CO2 reduction. TNNTs were prepared by anodic oxidation on TiNb alloy sheets and CuFeO2/TNNTs were then prepared by coating precursor liquid onto TNNTs followed by heat treatment in argon atmosphere. The microstructures of CuFeO2/TNNTs and TNNTs before and after heat treatment were investigated by SEM and TEM. The phase compositions of CuFeO2/TNNTs were studied by XRD and XPS, and the light absorption performance were tested by UV–vis diffuse reflectance spectrum. Results show that TNNTs exhibit a regular nanotube arrays structure and this structure is well remained after the calcination at 650 °C. In addition, TNNTs show similar semiconductor properties to n-type TiO2, which enables them to be integrated with p-type CuFeO2 to obtain composite photocathodes with a p-n junction. The synthesized CuFeO2/TNNTs photocathode is well crystallized because no other crystalline iron or copper compounds are included in the prepared photocathode. Furthermore, the photocathode shows high light absorption and fast carrier transport due to the appropriate band gap and p-n junction. As a result, high photoelectrocatalytic CO2 reduction performance with high selectivity to ethanol is obtained on this photocathode.

Three-dimensional ordered macro/mesoporous carbon (3DOM/m-C) with high specific surface area was synthesized by colloid crystal template method with chemical activation by KOH and used as the adsorbent for removing malachite green (MG) in aqueous solution. The microstructures of the adsorbents were characterized by FESEM, TEM and BET, and the effects of initial dye concentration, contact time, solution pH, and temperature on adsorption performance were investigated. The results show that the 3DOM/m-C exhibits extremely high adsorption capacity of 3541.1 mg/g within 2 h, which could be attributed to the novel ordered hierarchical structure with mesopores on three-dimensional ordered macroporous carbon walls. And the adsorption behavior conforms to the pseudo-second-order kinetic and Langmuir adsorption isotherm. 3DOM/m-C can be recycled after being desorbed by absolute ethanol, and still maintains a high capacity of 2762.06 mg/g after 5 cycles.

Seeding of mesenchymal stem cells (MSC) into a porous scaffold, as the first step in bone tissue engineering, determines the initial cell spatial distribution and further generating of engineered bone grafts. The immersed boundary (IB)–lattice Boltzmann (LB) method is used to study the dynamic seeding behavior of cells in a simplified scaffold. In this method, the multiple-relaxation-time version of LB method is employed as the fluid solver. An energy constitutive model for the cell is coupled with the fluid using the IB method. An adhesive dynamics model is employed to simulate the stochastic formation and breakage of receptor–ligand bonds. The present method was first validated by studying a capsule deformation in a simple shear flow. The cell model was calibrated based on the deformation of the MSC in a constricted microfluidic channel. Then perfusion of cells into pore structures was simulated to characterize cell motion during the seeding process. The distribution of formed bonds indicates that cells most likely adhere to the pore throats. The cells present different motion characteristics due to distinct adhesion status. The number of bonds plays an important role in determining the adhesion status. The cell-scale deformation and adhesion involved in this study provide more detailed mechanism which is difficult to investigate through experiments. The present method can also be extended to large-scale realistic scaffold contributing to the optimization and development of the seeding process.

Herein, we report a special pulse potential method to increase methanol production and keep the CuxO/TiO2 nanotube array (TNT) catalyst active during photoelectrocatalysis reduction of CO2. The CuO/TNT catalyst was prepared via electrodeposition of copper on anodized titanium oxide followed by heat treatment. The variation of valence of copper in the photoelectrocatalytic reduction process was studied intensively by high-resolution transmission electron microscopy, XPS, and AES characterizations. Results show that the photocatalytically active CuO is apt to be reduced to elementary Cu during photoelectrocatalysis process, leading to rapid decay of photocatalytic activity. While for the case of pulse potential regime, another photocatalytically active oxide, Cu2O, will be produced on the surface during anodic pulse, which can effectively maintain the photocatalytic activity of catalyst. CV study indicates that the oxidation of Cu is prior to the oxidation of methanol, so the methanol oxidation hardly ever happens during anodic pulse stage. The catalyst applied in pulse potential regime provided a much larger photocurrent than that in constant potential regime over an extended period of time. As a result, the yield of methanol produced in optimized pulse potential condition is greatly increased, nearly twice that in constant potential regime.

Lithium (Li) dendrites formed from nonuniform Li deposition limit potential uses of Li metal as an anode material. Here, we report a lithiophilic 3D porous CuZn current collector that mitigates den...

The silicon@graphene composite as anode material was prepared by a spray–drying method combined with a low temperature reduction technology. XRD results show that the composite is composed of silicon and graphene confirmed by the FT–IR and Raman spectra. SEM and TEM results reveal that the silicon@graphene powders are the spherical shape with micron in diameter and graphene sheets are enwrapped with nano–silicon particles. The silicon@graphene composite shows an improved electrochemical performance, in which the sample can show the best electrochemical performance while the mass ratio of silicon and graphene oxide reaches to 1:4, delivering a high initial charge capacity of 1298.1 mAh g−1 at 100 mA g−1. Moreover, the sample can also show good rate performance, which indicates that it could be used as a promising anode material for Li–ion batteries.

Since hypochlorite (ClO−) possesses the ability that oxidizes electron-rich objects with accompanying variations in spectroscopic features, we present here an effective strategy for generating new molecular-level probe that will be compatible for application in ClO− detection. This optical sensor has been established on a donor-π-acceptor (D-π-A) electronic structure derived from a pyrene derivative appended by 2-thioxo-dihydro-pyrimidine-4,6-dione (abbreviated as Py-Pd). Specifically, it can serve as a dual-mode sensor which exhibits fluorometric and colorimetric responses to the presence of hypochlorite. The high sensitivity, selectivity, fast response time (30 s) as well as low detection limit (75 nM) have been realized. Extensive spectroscopic analyses support the oxidation cleavage of bridge C C linkage leads to the transformation of Py-Pd to pyrene-2-carbaldehyde (Py-CHO). Such real-time imaging of hypochlorite has been also achieved in live cells and zebrafish model. In this sense, this molecular-based system can be employed as an indicator for early evaluation of optical responses of reactive oxygen species.

A simple, rapid and low-cost solar irradiation method to prepare highly fluorescent carbon dots has been demonstrated by using citric acid and o-phenylenediamine as precursors. The whole concentrated light sintering process is completed within 2 min and this nitrogen doped carbon quantum dots exhibit striking blue luminescence. Except the conventional ultra-violet (378 nm) pumped emissions, the specific up-converted photoluminescence signal is able to extend the excitation sources to near-infrared range (750 nm). Moreover, carbon dots are very sensitive and selective to the presence of Hg2+ ions. Two different responsive ways (down-conversion and up-conversion) have been employed for the first time and the limits of detection are determined to be 1.3 nM and 0.06 nM respectively. Its pH dependence has been discussed and the evolution curves indicate such carbon-based nanomaterial possess unique features within a wide pH range. This study focuses on efficient solar energy conversion and provides new insights of carbon dots with multi-modal sensing capabilities.

Ti3C2Tx MXene has been reported to be a metallic two-dimensional (2D) material with high conductivity, whereas its photoluminescence (PL) mechanism is still under debate. Herein, we demonstrate that large Ti3C2Tx MXene flakes exhibit tunable PL under ambient conditions. The as-prepared Ti3C2Tx MXene flakes emit blue, yellow-green and red light under different excitation wavelengths. Their PL emission wavelengths redshift as the excitation wavelength changes from violet to red light. Surface modification of the MXenes can further tune the PL peak wavelength into the near infrared region. Using density function theory (DFT) calculations, this excitation wavelength-dependent PL can be correlated to TiO2 defects that exist on the surface of Ti3C2Tx. Our study expounds on the optical properties of Ti3C2Tx MXene and is helpful for comprehensively understanding this novel material.

As soft materials represent new features that offer long-range orders, they have received considerable interests in optoelectronic fields. In this contribution, the assembly and characteriz...

Efficient ways for the trace level monitoring of Cr2O72− have generated considerable attention in the fields of medical diagnosis and environmental protection. In current research, the water-soluble carbon dots (CDs) have been developed via the precursors of 1,3-phenylenediamineand citric acid. The quantum dots with particle size of 3–4 nm have been prepared based on a simple one-pot ultrasonic irradiation method and demonstrate bright blue emission at 440 nm. Its excitation-dependent feature has been explored and the achieved emission evolves from blue (440 nm) to green luminescence (528 nm). Photophysical studies support that CDs can be remarkably quenched by the presence of chromate due to inner filter effect. In addition, the absorption curves demonstrate that carbon dots possess highly selective and sensitive responses to Cr2O72− through color changes. The dual sensing modes (fluorescence and colorimetric detection) can be well-established for the recognition of chromate and the detection limits are calculated to be as low as 140 nM and 410 nM respectively. To further evaluate the analytical potentials of such nano-platform, the concentration of Cr2O72− have been determined in real water and river samples.

Considerable interest in using lanthanide complexes in optics have been well-known persisted for a long time. But such molecular-based edifices have been excluded from practical application because of their poor thermal or photo stabilities. Here a novel europium embedded layered double hydroxide (Mg-Al LDH-Eu) has been established and such an inorganic-organic framework demonstrates improved thermal performance due to hydrolysis and poly condensation of the trimethoxysilyl-unit. In addition, the incorporation of a functional building block such as ethylenediamine triacetic acid can significantly minimize the negative effects of hydroxyl groups. In the presence of tetracycline (Tc), the nanoprobe exhibits an "off-on" change in aqueous solution, and the red luminescence can be excited in the visible light range (405 nm). It provides a very sensitive signal response to Tc with an excellent linear relation in the range of 0.1 μM to 5.0 μM, and the detection limit of this probe is measured to be 7.6 nM. This nanoplatform exhibits low cytotoxicity during in vitro experiments and can be employed for the detection of tetracycline in 293T cells.

A sensitive dispersive micro solid-phase extraction coupled with HPLC has been developed for preconcentration and determination of three flavonoids (quercetin, kaempferol, and isorhamnetin) in complex matrix samples. Parameters that affect extraction efficiency have been optimized. The optimal extraction conditions are using 2 μg/mL of crab shell as the sorbent, extraction for 2 min at pH 7, and then eluting with 100 μL of methanol. As a result, the method shows good linearity (R > 0.9994), low LODs (even 0.08 ng/ml) and satisfactory recovery in real honey and rat urine samples. As an eco-friendly biomaterial, crab shell powder is used as sorbent in pretreatment of flavonoids, and its adsorption mechanism has been investigated for the first time. Compared with the other reported methods, the proposed strategy is time-saving, eco-friendly, and highly sensitive using HPLC (even achieving MS grade sensitivity).

Most of reported I-III-VI2 type chalcopyrites have been developed as indispensible materials for potential application in photovoltaic solar cells, magnetism or thermoeletrics. The exploration of its photoluminescence potentials has been very limited and the chemical sensing using fluorescence to signal a recognition event is realized by way of CuFeSe2 nanocrystals. A novel solution-based synthesis strategy has been developed for the preparation of CuFeSe2 quantum dots (QDs) via oleylamine and dodecanethiol as precursors. QDs possess an intense blue luminescence at 431 nm and excitation-dependent features are recorded. The nanocrystals exhibit transformation from ferromagnetism to paramagnetism state between 4 K and 298 K. Another distinct advantage of the quantum dots will be the signaling pathway in response to external analytes. It gives rise to a rapid and selective assay of Cr2O72- through an “on-off” switching process. A linear equation can be obtained in the range from 0 to 47.5 μM and the detection limit has been determined to be 0.46 μM. This cost-effective method will pave the way for the efficient synthesis of ternary chalcopyrites and provide suitable chemical routes for sensing purposes.

The generation of novel optical sensing structures through the lanthanide coordination has been a key scientific endeavor. The design of molecular indicator for chemical response is derived from the assembly of a polymeric-based ternary europium (III) complex system (Eu(NTA)3L/PVA (NTA = 4,4,4-trifluoro-1-(naphthalen-2-yl)butane-1,3-dione, L = 2-(4-(4-(allyloxy)phenyl)-6-(pyridin-2-yl)pyridin-2-yl)pyridine, PVA = poly(vinyl acetate)). The electrospinning technique has been employed to create a nanometer scale membrane and this functional film with ultrafine fibers (diameter of about 110 nm) exhibits intense red light at 618 nm under ultra-violet excitation of 340 nm. The luminescent signal transduction involves the interaction of hydrogen chloride (HCl) with the organic ligand. The strong acidity of the analyte induces dissociation of complex network and the evolution of emission from red to blue has been observed. The fabricated nanosensor demonstrates rapid response time (

A robust, one-pot synthesis of polymeric nanocluster in polar medium has been reported based on the assembly of polyethyleneimine (PEI) and p-phenylenediamine (PPDA). A number of process parameters including molecular weights of PEI, ratios between PEI and PPDA, reaction time, pH condition and solvent polarity have been discussed. This novel nanomaterial can exhibit striking blue-greenish emissions upon the excitation at 377 nm. More importantly, it is highly sensitive to the titration of copper ions and detection limit has been determined to be as low as 11.27 nmol. These results will pave the way for constructing next generation of polymeric devices.

It is a challenge to commercialize tin dioxide-based anodes for lithium-ion batteries due to their low rate capability and poor cycling performance of the electrodes. Herein, we synthesized a three-dimensional Co3Sn2/SnO2 nanocomposite on copper foam (3D-CS@CF) via a simple method followed by calcination, and employed it as an anode for lithium-ion batteries. The experimental results reveal that the Co3Sn2 and SnO2 nanoparticles were uniformly loaded on the copper skeleton, and the 3D-CS@CF nanocomposite possessed a cross-linked 3D network. As a binder- and conductive-free anode for LIBs, 3D Co3Sn2/SnO2 exhibited good electrochemical performance with a high reversible capacity of 1010.5 mA h g−1 at a current density of 250 mA g−1 after 100 cycles. The extraordinary performance can be ascribed to the unique 3D architecture of the 3D-CS@CF, which inhibits aggregation and accommodates volume expansion, providing a path for the fast ionic diffusion and electron transport. The positive synergistic effect of Co3Sn2 and SnO2 nanoparticles also benefits the electrochemical reaction process.

To overcome the shortcomings of poor conductivity and large volume change, we proposed a novel three-dimensional ordered macroporous Cu/Sn (3DOM Cu/Sn) composite material as the anode of lithium-ion batteries (LIB). Electron microscopies and X-ray diffraction revealed that this new 3DOM Cu/Sn composite has the surface of the 3DOM Cu framework covered with a uniform layer of Sn nanoparticles. As a binder-free anode of LIB without conductive additives, this 3DOM Cu/Sn composite demonstrated an extremely high rate capability of about 707 mAh/g at 5C, which is 4 times higher than that of bare Cu/Sn anode, and excellent durability of 851 mAh/g up to 250 cycles. The post-test analysis showed that extraordinarily electrochemical performances of this composite anode are ascribed to the unique 3DOM microstructure.

Europium incorporated molybdenum carbide (Mo2C) has been assembled at 800 °C based on a single step and the synthesis processes have been discussed. (NH4)6Mo7O24·4H2O has been employed as a precursor and p-phenylenediamine has been selected as the carbon source. In contrast to conventional organic dyes, this novel lanthanide-activated phosphor provides red luminescence in the form of higher monochromatic purity due to the parity forbidden transitions. More importantly, the emission intensity of 5D0 → 7F2 transition increased depending on the incorporation of europium ions and the most suitable doping concentration will be 0.3 mmol. The utilization of f–f transition of Eu3+ in molybdenum carbide has made the red emission materials accessible for application in the area of display, electronics and bio-imaging.

An efficient strategy for the synthesis of excitation-independent carbon nanodots has been provided. This functional nano-scale particle has been assembled by using citric acid and urea as raw materials through a microwave irradiation process in the absence of further surface modifications. The achieved nanomaterial demonstrates intensive green emissions and can be dispersible in aqueous environment. In particular, cerium (III) ion is able to quench its fluorescence emission intensity selectively and an “on-off” change has been observed. A good linearity between the concentration range of 10−6–10−4 M has been realized and the detection limit is determined to be 0.7 μM. More importantly, we report a color-evolution based paper sensor for effective monitoring of Ce3+ by incorporating fluorescent nanoprobe onto the cellulose paper substrate.

The development of nanoprobes with high sensitivity and specificity for tumor marker detection has gained increasing attention in biological applications. Here, we have designed and synthesized a novel 4,4',4”,4”'-(ethene-1,1,2,2-tetrayltetrakis(benzene-4,1-diyl))tetrakis (1-(4-bromobenzyl)pyridin-1-ium) bromide (TPE-4N+) based aggregation induced emission (AIE) fluorescent sensor and it gives rise to electrostatic adsorption towards hyaluronic acid (HA), resulting in an effective emission recovery in yellow-greenish region. In the presence of hyaluronidase (HAase), the enzymatic digestion between HA and HAase induces the fluorescence quenching and this “on-off” change has been analyzed by two consecutive linear equations. The low detection limit is determined to be 0.02 U/mL by quantitative evaluation and its practical application has been verified by detecting human urine samples. It is promising that this new approach can be utilized to study a wide variety of other depolymerization reactions.

A novel strategy to highly sensitize terbium luminescence through 3-carboxyphenylboronic acid as the antenna ligand has been realized and the hybrid inorganic-organic probe has been assembled based on the silver nanoparticles. Its green emission is turned off in the presence of dopamine and the detection process is within 2–3 s. Cyclic voltammetry curves showed that a glassy carbon electrode modified with this lanthanide nanostructure demonstrated favorable electrocatalytic activity for the oxidation of dopamine in phosphate buffer. The developed nanosensor gave rise to a linear correlation depending on dopamine concentration and the detection limit was determined to be 0.41 μM. This dual-modal (optical and electrochemical) probe exhibited excellent selectivity and enough stability. The feasibility of the terbium sensitized nanosensor for cellular imaging has also been reported. Two adherent cell lines (Hela cells and THP-1 cells) exposed to the nanoprobe demonstrated striking green luminescence and showed on-off changes in the regulation of dopamine.

Assembly of a new functional organic linker, (dimethyl 4-(carbaldehyde oxime) pyridine-2,6-dicarboxylate, L1), with europium ions modified Uio-67 leads to Uio-Eu-L1, which is shown to be a new molecular-based probe with high sensitivity and selectivity for ClO−. The detection limit is calculated to be as low as 16 nM. To our knowledge, this is the first report of a sensitive europium sensor for ClO− established on the oxime isomerization reaction. The nature of organic L1 sensitizer within the complex has been demonstrated to control the photoluminescence effectively. The “off-on” signal changes can be realized by oxidative deoximation reaction induced recognition of hypochlorite. More strikingly, both continuous-mode lanthanide emission (steady-state photoluminescence measurement) and time-gated luminescence detection are collected in the presence of several interference organic dyes. This remarkable optical feature will allow easy spectral and discrimination of their emission bands from separation of noisy signals.

Lithium metal anode is regarded as the "holy grail" due to its extremely high specific capacity, low density and low reduction potential. However, Li dendrite growth reduces coulombic efficiency and causes safety accidents synchronously. In this paper, a rational designed three-dimensional ordered macroporous Cu is used as current collector for Li metal anode with excellent electrochemical performance, which is prepared by colloidal template method combined with copper electrodeposition. The novel porous Cu/Li anode with the pore size of 450 nm can stably run for 750 h at 0.2 mA/cm2 with a small Li electroplating/stripping overpotential (

An efficient way to assemble Fe3O4@SiO2-NH2 nanocomposite has been developed by coupling (3-aminopropyl)trimethoxysilane onto surface of core-shell structure through facile impregnation of Fe3O4@SiO2 decorated with amino groups. The key step during the synthesis involves the incorporation of organic fluorophore and amines are treated with 1,8-naphthalic anhydride. The achieved hybrid inorganic-organic nanoparticle gives rise to blue emissions and shows enough stability. Furthermore, Cu2+ can be recognized by the organic building block via coordination reaction and the “on-off” quenching effect is observed. The nanosensor provides a response concentration range (1–6 μM) to Cu2+ with the detection limit of 0.65 μM. Owing to the magnetic properties, the hybrid nanoprobe can be easily retrieved from aqueous solution for repeated uses via magnetic separation (35 s). This approach will offer an alternative way for designing novel detection systems in biological related fields.

Carbonaceous materials have long been developed to utilize "nano-spaces" and numerous guest species could be encapsulated. A remarkable fluorescence difference has been observed after newly designed pyropheophorbide-a-appended carbon nanohorns were incorporated in a cellular medium and confocal microscopy was employed for the determination of the intracellular localization. Our study supported the role of carbon nanohorns as carriers of photodynamic therapy (PDT) agents and their heating behavior was discussed. We have developed a theranostic platform based on photosensitizer-conjugated carbon nanostructures and this system has been applied in an animal model. In addition, a negligible toxicity of CNH-Pyro was found in body weight experiments and histopathological examination of the major organs.

Herein, we report a simple approach to synthesize high-performance and structurally stable CuO nanoparticles catalyst embedded in TiO2 nanotube arrays for CO2 reduction. To summarize, anodic TiO2 nanotube arrays (TNTs) were electrochemical reductive doped in 1 mol/L (NH4)2SO4 solution to form an activated surface. Then CuO nanoparticles were successfully filled into the pores pace of TNTs by electrodeposition and heat treatment. The effects of Ti(Ⅲ) reduction doping were discussed by means of electrochemical impedance spectroscopy (EIS) and X ray photoelectron spectroscopy (XPS). Results show that partial Ti(Ⅳ) in TNTs can be reduced to Ti(Ⅲ) by electrochemical reduction, which leads to a significant improvement in TNTs surfactivity and then benefits the deposition of Cu nanoparticles to form a stable embedded structure. As a consequence, the composite electrodes showed higher photoelectrocatalytic performance for CO2 reduction. The maximum current of CuO-TNTs composite electrodes is up to −1.37 mA/cm2 at −0.5 V and high selectivity for methanol synthesis is also obtained in this case. At the same time, the amount of methanol produced by the CuO/self-doped TNTs composite electrode is about 15% higher than that by the CuO/TNTs electrode without reductive doping.

Thickness controllable SiO2 film was prepared on γ-TiAl alloy by cathodic electrodeposition. The oxidation behaviour of the specimens at 900 °C was studied. The effects of SiO2 electrodeposition parameters, such as electrolysis time and deposition current density, on the morphology, structure and high temperature oxidation performance of the film were investigated. Results shown during thermal oxidation, the electrodeposited SiO2 film could react with the TiAl alloy to form an alumina- and silicon-enriched glass-like oxide scale, which can prevent the inward diffusion of oxygen from air to the film/alloy interface, resulting in the remarkable decreased oxidation rate of the alloy.

A three-dimensional (3D) Cu/Fe3O4 anode material was synthesized successfully via a simple and flexible route. Cu nanowires grew on Cu sheet directly by oxidation and reduction as 3D current collector, Fe3O4 nanosheets were coated on the collector surface by electrodeposition to form 3D Cu/Fe3O4 nanocomposite. The characterization results showed that oxidation time affects the morphology of Cu nanowires greatly, the collector has optimum 3D nanostructure at 200 s oxidation with high performance. The 3D Cu/Fe3O4 anode possessed high cycling capability, the capacity reached 700 mAh/g after 300 cycles at 0.5 A/g. And it exhibited high rate performance, the capacity reached 482 mAh/g at 2 A/g and it recovered to 853.5 mAh/g at 0.2 A/g after 100 cycles of different rate tests. The high performance is ascribed to the unique 3D nanostructure of current collector, which provides sufficient space for large volume change and stress release, and reduces the distance for transporting lithium ions and electrons.

An aluminum- and fluorine-enriched anodic film was fabricated on TiAl alloy by anodizing in NaF-contained methanol solution. The high-temperature oxidation resistance and protection mechanism of the anodized TiAl alloy were investigated. It showed that the formation of aluminum-enriched oxide scale originates from halogen effect and quite small anodization current density is essential to improving the high-temperature oxidation resistance. Upon oxidation at 850 °C for 100 h, no cracks and/or spallation were exhibited on the anodized TiAl alloy. At temperature higher than 300 °C, titanium fluoride will sublimate, accompanying with the transformation of aluminum fluoride into protective Al2O3 layer, as was indicated by XPS analysis. This freshly generated Al2O3 layer, together with the anodization formed one, can efficiently inhibit the outward diffusion of Al and inward diffusion of oxygen, thereby improving the high-temperature oxidation resistance of the TiAl.

For lithium-ion batteries (LIBs), the current collectors are indispensable components for loading electrode materials. The electrolytic copper foils with different tensile strength were selected to study the strengthening mechanism of copper foil. Through refining crystal grains and strengthen the crystal orientation of copper foils, the tensile strength can be considerably improved. For normal strength copper foil, the crystal orientation is (200) plane and the average grain size is 1.428 µm. For high strength and super strength copper, the crystal orientation are both (220) plane, and the average grain sizes are 1.09 µm and 862 nm. Moreover, the influence mechanism of texture to strength was studied by characterizing the dislocation density of the copper foils. Through which, the dislocations and substructures inside the crystal grains that produced by the release of residual internal stress can be observed, and the deformation of the crystal grains can be hindered during a stretch process.

In this work, graphene oxide (GO) and copper ferrite composite was synthesized on Fe-Ni foam via a one-step hydrothermal method. The foam substrate not only acts as holding material for GO and copper ferrite, but also makes this adsorbent convenient to recycle. The morphology and surface composition of the graphene oxide/copper ferrite foam (GCFF) were analyzed by scanning electron microscopy (SEM), transmission electron microscope (TEM), X-ray photoelectron spectroscopy (XPS), and Raman spectra. The adsorption behavior of As(III) and As(V) onto the GCFF was studied as a function of solution pH, temperature, contact time, initial concentrations, and competing ions. Results show this GCFF is an efficient adsorbent for arsenic with high adsorption capacities for both As(III) and As(V) owing to the synergistic effect of CuFe2O4 and GO. The maximum adsorption capacities for As(III) and As(V) are 51.64 and 124.69 mg g−1, respectively. Adsorption isotherms study indicates a Langmuir model of adsorption. In addition, the GCFF also reveals good recyclability due to the unique foam structure and the adsorption capacity is almost not deteriorated after eight recycles. Column experiment suggests that 96% As(V) can be removed from water solution after 100 bed volume test.

In contrast to conventional nanomaterials or organic dyes, carbon dots possess a variety of appealing properties including chemical inertness and easy manipulation and they can be dispersed in water. Herein, the use of a concentrated solar irradiation sintering strategy for the rapid and efficient assembly of carbon dots (CDs) has been reported for the first time. This novel alternative pathway effectively uses a renewable source and the process is feasible and environmentally sustainable. Three kinds of CDs were obtained, which demonstrate blue, green and red luminescence. Highly efficient blue-emitting CDs with quantum yield as high as 81% have been realized. The blue and red carbon dots give rise to excitation-independent emission peaks at 443 and 592 nm, respectively; however, the green CDs feature a continuous shift and the evolution of emission curves varies from 480 to 538 nm. By regulating the composition and ratios of these tri-color carbon dots, the emission band generates peaks from blue to red light, which cover almost the entire visible light range. Upon a single ultra-violet excitation at 365 nm, a white-light emission with CIE coordinates of (0.28, 0.33) was detected and the signal was very close to pure white light (0.33, 0.33). This study introduces a new method for fabricating low-cost nanoparticles as potential phosphors for light-emitting uses.

A novel IrO 2 coating titanium anode (IrO 2 /TNTs/Ti) without cracks in microstructure has been prepared via a thermal decomposition method using heat-treated TiO 2 nanotube arrays (TNTs) as interlayer. This electrode shows a significantly higher activity for oxygen evolution reaction (OER) and longer lifetime than the IrO 2 /Ti electrodes without a TNTs layer. The influence of IrO 2 amount and calcination temperatures on oxygen evolution as well as morphology and phase characteristics were studied by electrochemical measurements, X-ray diffraction (XRD) and scanning electron microscopy (SEM) observations. The results show that the catalytic properties of oxide electrodes highly depended on the loading amount of IrO 2 and calcination temperatures. The electrode fabricated at calcination temperature of 600 °C showed a weak electrocatalytic activity due to high degree of crystallinity, grain growth, accumulation of active component and the collapse of TNTs. On the contrary, the IrO 2 /TNTs/Ti electrode prepared at low calcination temperature (400 °C) possesses extremely more surface active sites and high activity for oxygen evolution in the initial stage, but its service life is very short. The IrO 2 /TNTs/Ti electrode was found to achieve the lowest film resistance and the charge transfer resistance at an optimal loading amount of 6 g/m 2 . By simply optimizing both calcination temperature and IrO 2 loading amount, IrO 2 /TNTs/Ti electrode with high activity and long lifetime can be fabricated.

A nanostructured NiCo@NiCoOx core-shell layer for oxygen evolution reaction in alkaline solution was prepared. Firstly, a NiCo-SiO2 composite film was electro-codeposited from a solution containing (NH4)2SiF6, NiSO4, and CoSO4. Then the as-prepared composite layer was underwent consecutive CV scans in concentrated alkaline solution. During this process, the SiO2 template was etched and the NiCo component was activated leading to the generation of a NiCoOx shell. Results shown that this nanostructured NiCo@NiCoOx core-shell layer can provide a current density of 100 mA cm−2 in 1.0 M KOH at a low overpotential of 337 mV and exhibits good stability towards water oxidation. The excellent OER performance is enabled with the unique metal-oxide/hydroxide core-shell structure, which allows high electrical conductivity in the core and high catalytic activity on the shell.

A novel three-dimensional ordered macroporous (3DOM) Cu/Fe 3 O 4 composite film was prepared by electrodepositing ferroferric oxide (Fe 3 O 4 ) on the 3DOM Cu current collector. Characterizations via electron microscopies and X-ray diffractions confirmed that achieved 3DOM Cu/Fe 3 O 4 composite inherited originally ordered porous structure, but has a layer of nanosized Fe 3 O 4 on the surface of the 3DOM Cu framework. The obtained 3DOM Cu/Fe 3 O 4 composite films were directly used as anodes of lithium ion batteries in the absence of conducting additives or binders. Results from electrochemical evaluations exhibited that the 3DOM Cu/Fe 3 O 4 anode could deliver a stable capacity of 800 mAh g −1 up to 400 cycles, while fast capacity degradation with 200 mAh g −1 retained after 100 cycles was observed on Fe 3 O 4 deposited on plane Cu substrate. The superior behavior of the 3DOM Cu/Fe 3 O 4 composite anode is ascribed to its unique porous structure, which provides sufficient space for large volume change of Fe 3 O 4 and greatly reduces the diffusion distance for Li-ion in the active material.

The sluggish kinetics of oxygen evolution reaction (OER) is the most challenging technical problem in water splitting. Here, we reported a new type of cauliflower-like NiCo 2 O 4 (CF-NiCo 2 O 4 ) film which was co-electrodeposited with silica for oxygen evolution reaction. Structure and morphology of the obtained films were characterized using X-ray photoelectron spectroscopy, X-ray diffraction, scanning electron microscopy and transmission electron microscopy. Electrochemical properties of the CF-NiCo 2 O 4 film were evaluated by quasi-steady state polarization curve, cyclic voltammetry and electrochemical impedance spectroscopy. Results show that the enhanced electrocatalytic activity of the CF-NiCo 2 O 4 film toward OER is a synergistic effect of improved intrinsic catalytic activity and increased surface area.

In this study, a green ionic-liquid based vortex-synchronized matrix solid-phase dispersion (VS-MSPD) combined with high performance liquid chromatography (HPLC) method was developed as a quantitative determination method for four anthraquinones in Cassiae Semen. Two conventional adsorbents, C18 and silica gel were investigated. The strategy included two steps: Extraction and determination. Wasted crab shells were used as an alternative adsorbent and ionic liquid was used as an alternative solvent in the first step. Factors affecting extraction efficiency were optimized: A sample/adsorbent ratio of 2:1, a grinding time of 3 min, a vortex time of 3 min, and ionic liquid ([Domim]HSO4, 250 mM) was used as eluent in the VS-MSPD procedure. As a result, the established method provided satisfactory linearity (R &gt, 0.999), good accuracy and high reproducibility (RSD &lt, 4.60%), and it exhibited the advantages of smaller sample amounts, shorter extraction time, less volume of elution solvent, and was much more environmental-friendly when compared with other conventional methods.

Cyclic aging tests of LiNi1/3Co1/3Mn1/3O2 batteries are performed at 25℃, 45℃ and 60℃. Several non-invasive electrochemical techniques, such as incremental capacity analysis, differential voltage analysis and capacity difference analysis, are employed to deduce degradation mechanism. The degradation mechanism of batteries is similar at different temperatures. Loss of active positive material follows a linear function at all conditions and increases by elevating temperature. Due to the graphite's volume expansion and contraction, loss of active negative material is observed at the first 100 full cycle equivalents. Then, it disappears until the appearance of a dense lithium-containing passivation layer. This covering layer is mainly from lithium deposition on the negative electrode surface. With this lithium-impermeable covering layer's growth, the homogeneity of active lithium distribution is successively reduced, and loss of negative material increases gradually. Moreover, a worst cyclic performance is found at 45℃, where the homogeneity of electrodes reduces rapidly. All results reveal that loss of active materials and lithium inventory loss only influence capacity loss. The evolution of the covering layer on the negative electrode surface is the deciding factor for cycle life.

Large overpotential and poor cyclability are the main constraints for lithium-oxygen batteries (LOBs), which are usually related to the slow decomposition of the discharge product during oxygen evolution reaction (OER) of charging process. In this paper, a novel method of pulse current charging is developed for solving these problems. The results show, compared with the normal constant current samples, when duty cycle is 50% and frequency is 1 Hz and, the overpotential decreases up to 25% and the cycle life improves more than 4 times. During charging process, pulse current can reduce the concentration polarization and promote the decomposition of Li2O2, and increase the reaction kinetics of OER process, leading to the reduction of overpotential and improvement of electrochemical performance.

The rational design and synthesis of highly-efficient cathode catalysts are of importance to high-performance lithium-oxygen batteries (LOBs). In this work, We use crab shell waste as a carbon source through carbonization, activation, and sol-gel method to synthesize activated functional carbon (AFC) and fabricate CoPt/AFC catalyst for Li-O2 batteries. The as-prepared AFC possesses abundant hydroxyl (OH‒) and amino (NH2‒) groups as the link bridge for enhancing the metal-support interaction. Revealed by the density functional theory calculations, the tuned adsorption for intermediates and reduced overpotentials for both oxygen reduction and evolution reactions (ORR and OER) are achieved on such the composite structure. Experimentally, CoPt nanoparticles are evenly distributed on the surface of OH‒ and NH2‒ functionalized porous carbon through the sol-gel method. The abundant pore structures in the resultant catalyst (CoPt/AFC) can provide sufficient room for depositing discharge products. Moreover, the side reactions are effectively suppressed, as evidenced by the in-situ Raman spectra. As a result, the LOBs with the CoPt/AFC cathode present excellent electrochemical performances with a high discharge specific capacity of 8.25 mAh cm−2, a low overpotential of 0.47 V, and good cycling stability of 156 cycles.

A ferromagnetic three-dimensional ordered macroporous TiO2/CoPt/α-Fe2O3 (3DOMTCF) nanocomposite was synthesized via a sol–gel approach templated by poly(methyl methacrylate) (PMMA) microspheres. After magnetization, it exhibited an extremely high reversible capacity and a long cycle life, which were ascribed to the internal magnetic field for reusing pulverized active materials and its unique structure.

A nanostructured nickel–cobalt alloy with an oxide layer was fabricated and its superior catalytic activity towards the electrochemical oxygen evolution reaction in alkaline media was investigated. Firstly, a NiCo–SiO2 composite film was prepared via a potentiostatic electro-codeposition method. Then the SiO2 template was etched and the NiCo component was activated leading to the generation of a NiCoOx layer during consecutive CV scans in concentrated alkaline solution. The results show that this nanostructured NiCo alloy with the oxide layer can provide a current density of 100 mA cm−2 in 1.0 M KOH at a low overpotential of 326 mV and exhibits good stability towards water oxidation. The excellent OER performance is enabled with the unique metal-oxide structure, which allows high electrical conductivity in the metal and high catalytic activity on the oxide.

In the present study, Ni-Ti-O nanotube arrays (Ni-Ti-O NTs) were fabricated by anodizing NiTi alloy in a mixed solution consisted of ethylene glycol and glycerol. Then the Ni-Ti-O NTs were suffered annealing treatment under hydrogen atmosphere, leading to the significant improved electrocatalytic performance. The morphologies, the phases and the surface electronic states of Ni-Ti-O NTs samples before and after annealing were characterized by SEM, XRD and XPS, respectively. And their electrocatalytic properties for methanol oxidation were investigated by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) in the alkaline media. Results show that electrocatalytic activity of the Ni-Ti-O NTs samples annealed under H 2 exhibits a significant improvement because of the increases of the conductivity and the active sites provided by reduction of Ni 3+ . The Ni-Ti-O NTs samples with lower crystallinity annealed at 500 °C for 2 h have better electrocatalytic performance for methanol electro-oxidation in alkaline medium. The peak current density increases after a consecutive sweep for 1000 times and varies indistinctively after placing in the air for 30 days, indicating the excellent long-term electrocatalytic stability. The in situ formation of Ni-base material catalyst in Ni-Ti-O nanotube benefits improvement of the catalytic properties during long-term operation. The Ni-Ti-O NTs/Ni-Ti alloy is a desirable substitute of catalysts support material or it is also a promising electrocatalytic electrode for direct methanol fuel cells.

Developing an oxygen evolution reaction (OER) electrocatalyst with low cost, abundant reserve and excellent performance is essential for extensive application of clean and renewable hydrogen energy. The present work proposed to fabricate hierarchical NiSe-based nanocone arrays on stainless steel (SS) for OER. Firstly, nickel nanosheet array was electrodeposited on SS (Ni/SS). Then, the Ni/SS was selenized via hydrothermal to form NiSe@Ni/SS. Finally, activation was performed by consecutive CV scans to convert NiSe into O-NiSe (O-NiSe@Ni/SS). The influence of selenization temperature and duration time on the morphology and OER performance were systematically investigated. Results showed that the optimized O-NiSe@Ni/SS performed high OER activity and good stability in 1.0 M KOH (pH = 14). To provide a current density of 10 mA cm−2, an overpotential of 290 mV was needed and a small Tafel slope of 48 mV dec−1 was observed. The good OER performance was attributed to the reduced charge transfer resistance and increased electrochemical active sites.

Activation of cancer cell apoptosis and understanding its working mechanism play a critical role in formulating effective cancer treatment strategies. Herein, we report the design, synthesis, and biological evaluations of a selenium-containing fluorescent apoptotic agent MPSE. MPSE enabled the tracking and imaging of cancer cell apoptosis process. Its emission at 550 nm turned off in the presence of thioredoxin reductase (TrxR) in mitochondria, by forming a non-emissive compound MP. This emission “turn-off” phenomenon allows the monitoring of reactive oxygen species (ROS) induced mitochondria damages. As dysfunctional mitochondria were removed by lysosomes, MP entered lysosomes and its protonation led to bright emissions peaked at 475 nm. The new emission enables the tracking of lysosome activation during the apoptosis process. With the help of MPSE, along with other biological techniques, we have revealed three signal transduction pathways that activate cancer cell apoptosis and inhibit tumor cell proliferation. Our results showed that MPSE was highly useful in elucidating the working mechanism of theranostic-based optical apoptotic agents. We hope that understanding this mechanism will greatly facilitate the development of new cancer treatments.