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In this study, a modeling method for investigating the dynamic characteristics of a hydraulically driven shell manipulator with revolute clearance joints is presented. This model accounts for the effect of the clearance, the flexibility of the rotating beam, and the coupled dynamic characteristics of the hydraulic cylinder. A modified contact force model was developed to simulate the physical properties of realistic revolute joints with small clearances, heavy loads, and variable contact stiffnesses and damping coefficients with variations of the indentations. Considering the strong coupling relationship between the hydraulic cylinder and the flexible beam, a system equation of motion combining the state variables of the hydraulic cylinder and mechanical system was established. The complex nonlinear friction force of the hydraulic cylinder motion was constructed using a modified LuGre model, and the parameters of the friction model were identified using intelligent identification algorithms. Moreover, a test system for the shell manipulator was established to achieve experimental validation. Finally, the effects of the clearance size and the stiffness of the cylinder support on the dynamic response were investigated.

Presented herein is an experimental study on the combustion of B4C/KNO3 binary pyrotechnic system. Combustion products were tested using X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy dispersive spectrometer (EDS). According to the results of tests and CEA calculation, the combustion reaction equation was established. The flames and burning rates were recorded by a high speed camera and a spectrophotometer. The effect of B4C particle size on the thermal sensitivity of B4C/KNO3 was investigated by differential scanning calorimetry (DSC) techniques. In addition, a reliable method for calculating the flame temperature was proposed. Based on the results of experiments, the combustion reaction mechanism was briefly analyzed. The burning rate, flame temperature and thermal sensitivity of B4C/KNO3 increase with the decrease of B4C particle size. The mass ratio of B4C/KNO3 has a great effect on combustion properties. Oxidizer-rich compositions have low flame temperatures, low burning rates, and provide green light emission. The combustion reactions of fuel-rich compositions are vigorous, and the B4C/KNO3 with mass ratio of 25:75 has the highest burning rate and the highest flame temperature.

The intrinsic activity of Co(OH)2 for oxygen evolution reaction (OER) may be elaborately improved through the suitable valence adjustment. Ce modification at electronic level is proved to be an efficient strategy owing to the flexible transformation of Ce3+/Ce4+. Herein, Ce0.21@Co(OH)2 with the optimized Ce doping have been fabricated to tailor the fast electron transfer for the enhanced activity and stability for OER. Firstly, the obtained core–shell structure composed of vertical loose Co(OH)2 sheets not only exposes a large number of active sites, but also provides channels for Ce doping. Secondly, the high pressure microwave with instantaneous heating can fast introduce Ce into Co(OH)2, obtaining Cex@Co(OH)2 with well dispersion and close integration. The intimated interaction between Ce and Co species may provide the “d–f electronic ladders” for accelerating electron transfer of the catalytic surface. Meanwhile, Ce promotes the formation of Co-superoxide intermediate and/or the release of oxygen, which is considered to be the rate-determining step for OER. The electrochemical measurements confirmed the low overpotential of 300 mV at 10 mA cm−2 and great stability of Ce0.21@Co(OH)2 for OER. This work demonstrates a meaningful approach to realize the tuned electronic structure through metal doping.

Single-atom catalysts (SACs) with well-defined and specific single-atom dispersion on supports offer great potential for achieving both high catalytic activity and selectivity. Covalent organic frameworks (COFs) with tailor-made crystalline structures and designable atomic composition is a class of promising supports for SACs. Herein, we have studied the binding sites and stability of Pd single atoms (SAs) dispersed on triazine COF (Pd1/trzn-COF) and the reaction mechanism of CO oxidation using the density functional theory (DFT). By evaluating different adsorption sites, including the nucleophilic sp2 C atoms, heteroatoms and the conjugated π-electrons of aromatic ring and triazine, it is found that Pd SAs can stably combine with trzn-COF with a binding energy around −5.0 eV, and there are two co-existing dynamic Pd1/trzn-COFs due to the adjacent binding sites on trzn-COF. The reaction activities of CO oxidation on Pd1/trzn-COF can be regulated by the anion-π interaction between a + δ phenyl center and the related −δ moieties as well as the electron-withdrawing feature of imine in the specific complexes. The Pd1/trzn-COF catalyst is found to have a high catalytic activity for CO oxidation via a plausible tri-molecular Eley-Rideal (TER) reaction mechanism. This work provides insights into the d-π interaction between Pd SAs and trzn-COF, and helps to better understand and design new SACs supported on COF nanomaterials.

In this work, hierarchically porous carbon spheres co-doped by iron and nitrogen were synthesized via in situ dehalogenation. The rich porous structure and relatively high specific surface area (210 m2/g) facilitate the formation of an ultra-fine Fe2N active phase and FeN4 active centers within the carbon matrix. Transmission electron microscopy and X-ray photoelectron spectroscopy analysis further reveal the presence of a dominant Fe2N phase and minor FeN4 bonds in the as-prepared Fe-N-C-pd-800 samples. Because of this, the oxygen reduction reaction (ORR) process can more readily take place on Fe2N than on FeN4, and the Fe2N phase enriched Fe-N-C-pd-800 carbon spheres exhibit a promising onset potential (Eonset=1.02 V) and half-wave potential (E1/2=0.86 V) in alkaline media. In addition, Fe-N-C-pd-800 also shows excellent methanol resistance and long-cycling stability.

The development of electric and hybrid electric vehicles has emerged as one of the most promising strategies for solving the global shortage of fossil energy problem. High-energy and high-power lithium-ion batteries are essential for achieving the large-scale commercialization of electric vehicles. Ni-rich layered-structure oxides appear to be one of the most ideal candidates for electrode materials owing to their high-energy density. However, severe degradation issues associated with chemical and structural instabilities have limited their further applications. This review summarizes recent progress toward the fundamental understanding of ternary layered-structure oxides with a particular focus on the key issues of ion intermixing, chemo-mechanical degradation, and phase evolution on the particle surface. The possible strategies, as well as perspectives for addressing these problems, are also proposed in this review as an effort to provide guidance on the further design of advanced layered-structure oxides.

Presented herein is a study on the ignition reaction kinetics and mechanism of B4C/KNO3 and B4C/KClO4 pyrotechnic smoke compositions using the non-isothermal thermogravimetry and differential scanning calorimetry techniques. The pyrotechnics in oxygen balance of − 10%, − 20% and − 30% were prepared for the experiments. The results of measurements showed that the pyrotechnics in oxygen balance of − 20% had the highest enthalpy. The activation energy (Ea) of ignition reactions was calculated by using Ozawa–Flynn–Wall (OFW) and Kissinger–Akahira–Sunose (KAS) methods. The Ea values of B4C/KNO3 and B4C/KClO4 were 139.5 and 214.6 kJ mol−1 calculated by OFW method, and 129.3 and 210.7 kJ mol−1 by KAS method. The differential and integral reaction mechanism functions of B4C/KNO3 and B4C/KClO4 were determined, respectively, by z(α) master plots method, f1(α) = 2(1 − α)[− ln(1 − α)]1/2, g1(α) = [− ln(1 − α)]1/2, and f2(α) = 3(1 − α)[− ln(1 − α)]2/3, g2(α) = [− ln(1 − α)]1/3. The pre-exponential factors, lnA = 11.6 and 22.3 min−1, were obtained by the intercept of KAS method for ignition reaction of B4C/KNO3 and B4C/KClO4 pyrotechnics. Based on the results, the burning rates, thermal sensitivities and application methods of B4C/KNO3 and B4C/KClO4 were predicted.

Aluminum nitride (AlN) was synthesized by combustion of spherical Mg–Al alloy particles in air. Alloy powder was freely poured on a sample table, which formed a cone with a diameter of 1-2 cm. A commercial electro-thermal furnace was used to ignite the cone to start the synthesis. During the combustion, the temperature was measured and the actual burning process was recorded by a video camera. The morphology and phase makeup of the raw powders and the synthesized AlN powders were analyzed by scanning electron microscopy and X-ray diffraction. The thermodynamic properties and ignition temperatures were studied using differential scanning calorimetry and thermogravimetric analysis. Moreover, the effects of the Mg–Al alloy particle size (212.8 μm, 124.1 μm, 61.1 μm, and 29.5 μm) on the morphology of AlN were investigated. The results show that the combustion of Mg greatly promoted the nitridation of Al and that Al in both large and small alloy particles could be completely converted into AlN. The combustion products of the alloy consisted of two different layers: an upper white layer containing MgO and a lower black layer containing AlN. More AlN whiskers formed when small particles were used. However, very small Mg–Al alloy particles hindered the formation of AlN whiskers.

The dynamic recrystallization (DRX) behavior of INCONEL 690 (IN690) alloy was studied using electron backscatter diffraction (EBSD) and transmission electron microscopy. Isothermal compression tests were performed on a Gleeble-3500 simulator under temperatures 950-1100 °C, strain rates 0.01-1 s−1, and the maximum true strain 0.8. An Avrami-type model was developed to investigate the DRX behavior of IN690; it was found to be extremely sensitive to the processing parameters of temperature, strain rate, and true strain. As temperature increased and strain rate decreased, the activation energy increased, thus accelerating movement of dislocation and migration of grain boundaries, causing DRX behavior acceleration. The DRX behavior is accompanied by dislocation rearrangement and annihilation. The DRX mechanism of IN690 is dominated by discontinuous dynamic recrystallization (DDRX) and supplemented by continuous dynamic recrystallization (CDRX). A key characteristic of DDRX is grain-boundary bulges, while CDRX features progressive sub-grain rotation, leading to migration of low-angle grain boundaries to high-angle grain boundaries. A series of constitutive models were embedded into finite-element method software to study the DRX behavior of IN690. The results show that the microstructure evolution regularity obtained by the simulation method is consistent with the experimental values, which provides a basis for computer simulations of the hot machining process.

Alloy-based materials are promising anodes for rechargeable batteries because of their higher theoretical capacities in comparison to graphite. Unfortunately, the huge volume changes during cycling...

The development of highly active catalysts for ammonia selective catalytic reduction (NH3-SCR) of NO at low temperatures and the exploration of efficient catalytic active sites are desirable but st...

A green H2O-promoted solvent-free hydroamination of electron-deficient terminal alkynes with amines has been developed. All secondary amines, including aliphatic and aromatic amines, gave the corresponding (E)-enamines in good to excellent yields, whereas primary aromatic amines afforded Z-configured products in moderate yields. Propiolates, propyn-1-ones, propynamides, and 1-(ethynylsulfonyl)-4-methylbenzene were explored in this Michael addition.

The criteria used by International Union for Conservation of Nature (IUCN) for its Red List of Ecosystems (RLE) are the global standards for ecosystem-level risk assessment, and they have been increasingly used for biodiversity conservation. The changed distribution area of an ecosystem is one of the key criteria in such assessments. The Stipa bungeana grassland is one of the most widely distributed grasslands in the warm-temperate semi-arid regions of China. However, the total distribution area of this grassland was noted to have shrunk and become fragmented because of its conversion to cropland and grazing-induced degradation. Following the IUCN-RLE standards, here we analyzed changes in the geographical distribution of this degraded grassland, to evaluate its degradation and risk of collapse. Past (1950-1980) distribution areas were extracted from the Vegetation Map of China (1:1,000,000). Present realizable distribution areas were equated to these past areas minus any habitat area losses. We then predicted the grassland’s present and future (under the Representative Concentration Pathway 8.5 scenario) potential distribution areas using maximum entropy algorithm (MaxEnt), based on field survey data and nine environmental layers. Our results showed that the S. bungeana grassland was mainly distributed in the Loess Plateau, Hexi Corridor, and low altitudes of the Qilian Mountains and Longshou Mountain. This ecosystem occurred mainly on loess soils, kastanozems, steppe aeolian soils and sierozems. Thermal and edaphic factors were the most important factors limiting the distribution of S. bungeana grassland across China. Since 56.1% of its past distribution area (4.9×104 km2) disappeared in the last 50 a, the present realizable distribution area only amounts to 2.2×104 km2. But only 15.7% of its present potential distribution area (14.0×104 km2) is actually occupied by the S. bungeana grassland. The future potential distribution of S. bungeana grassland was predicted to shift towards northwest, and the total area of this ecosystem will shrink by 12.4% over the next 50 a under the most pessimistic climate change scenario. Accordingly, following the IUCN-RLE criteria, we deemed the S. bungeana grassland ecosystem in China to be endangered (EN). Revegetation projects and the establishment of protected areas are recommended as effective ways to avert this looming crisis. This empirical modeling study provides an example of how IUCN-RLE categories and criteria may be valuably used for ecosystem assessments in China and abroad.

With the advent of nanotechnology, various modes of traditional treatment strategies have been transformed extensively owing to the advantageous morphological, physiochemical, and functional attributes of nano-sized materials, which are of particular interest in diverse biomedical applications, such as diagnostics, sensing, imaging, and drug delivery. Despite their success in delivering therapeutic agents, several traditional nanocarriers often end up with deprived selectivity and undesired therapeutic outcome, which significantly limit their clinical applicability. Further advancements in terms of improved selectivity to exhibit desired therapeutic outcome toward ablating cancer cells have been predominantly made focusing on the precise entry of nanoparticles into tumor cells via targeting ligands, and subsequent delivery of therapeutic cargo in response to specific biological or external stimuli. However, there is enough room intracellularly, where diverse small-sized nanomaterials can accumulate and significantly exert potentially specific mechanisms of antitumor effects toward activation of precise cancer cell death pathways that can be explored. In this review, we aim to summarize the intracellular pathways of nanoparticles, highlighting the principles and state of their destructive effects in the subcellular structures as well as the current limitations of conventional therapeutic approaches. Next, we give an overview of subcellular performances and the fate of internalized nanoparticles under various organelle circumstances, particularly endosome or lysosome, mitochondria, nucleus, endoplasmic reticulum, and Golgi apparatus, by comprehensively emphasizing the unique mechanisms with a series of interesting reports. Moreover, intracellular transformation of the internalized nanoparticles, prominent outcome and potential affluence of these interdependent subcellular components in cancer therapy are emphasized. Finally, we conclude with perspectives with a focus on the contemporary challenges in their clinical applicability.

The gold-catalyzed acetylene hydrochlorination reaction is an important process to produce vinyl chloride monomer in the polyvinyl chloride industry. The traditional catalyst of carbon-supported Au...

Copper-containing composites have been widely investigated among various sodium-layered cathode materials due to the low cost and abundance of the copper element. However, the electrochemical performance of these composites is usually deteriorated by the phase transitions corresponding to the stepwise charge/discharge curves, leading to an unsatisfactory capacity stability. Herein, we report that an improved electrochemical performance was achieved by substituting manganese with lithium in the Ni/Co-free P2-type Na0.6Mn0.8−xLixCu0.2O2−δ (x = 0, 0.05, 0.1, 0.15 and 0.2, δ > 0) composites with smooth charged/discharged curves. A capacity retention rate was increased from 54.3% to 82.8% over 200 cycles after adding 0.15 mole of lithium in per stoichiometric composites (Na0.6Mn0.65Li0.15Cu0.2O2−δ). Moreover, the rate performances were all enhanced in the lithium-incorporated composites compared to that of the pristine one. The interphase changes during and after cycling were studied by ex situ and in situ electrochemical impedance spectroscopy measurements, which prove that Li benefits the charge transfer and stabilizes the interphase of the Na0.6Mn0.65Li0.15Cu0.2O2−δ electrode. The in situ X-ray diffractometry results illustrate an alleviated crystallographic change in Na0.6Mn0.65Li0.15Cu0.2O2−δ compared to the Li-free electrode. These combined results provide explanations for the enhanced electrochemical performance after Li substitution in the Na0.6Mn0.8Cu0.2O2 composites from the aspect of the interfacial properties and structure variation. In addition, the online differential electrochemical mass spectrometry test demonstrates that the overall evolved CO2 gas in Na0.6Mn0.65Li0.15Cu0.2O2−δ cell is lower than that in the lithium-free cell during the initial cycle.

Developing efficient and durable electrocatalysts with uniform sizes for the hydrogen evolution reaction (HER) in the entire pH range and seawater is critical for scalable and sustainable hydrogen production. Herein, we report a supramolecular starch-assisted confinement–assembly–pyrolysis (SCAP) strategy for the synthesis of ultrasmall Rh2P nanoparticles with high dispersion and low loading anchored on N,P-doped porous carbon (NPC). The Rh2P/NPC composite exhibits an unprecedented HER activity with small overpotentials at 10 mA cm−2 (40 mV in 0.5 M H2SO4 and 17 mV in 1 M KOH), as well as superior stability in both acidic and alkaline media. In addition, the Rh2P/NPC catalyst also exhibits an excellent HER performance in the entire pH range. Especially, the Rh2P/NPC catalyst shows an electrocatalytic HER activity superior to that of a 20% Pt/C catalyst in natural seawater, especially under large current densities. It only needs 160, 341 and 411 mV versus RHE to achieve current densities of 10, 100, and 300 mA cm−2, respectively. To the best of our knowledge, this Rh2P/NPC material is the best electrocatalyst reported thus far for seawater electrolysis. Moreover, the Rh2P/NPC catalyst also shows good stability over a wide range of current densities. All these results indicate that the Rh2P/NPC catalyst can be used as a robust catalyst for hydrogen production via direct seawater electrolysis. In situ X-ray absorption spectra revealed the strong interaction between the Rh–P site and H2O during the HER catalytic process in 1 M KOH, revealing the positive role of the Rh–P site in the HER. Theoretical calculations demonstrate that the strong synergistic effects between Rh2P nanoparticles and NPC modify the electronic structure to accelerate the HER kinetics. More interestingly, the SCAP strategy not only yields a robust and pH-universal HER catalyst, but also enables a general, green, and gram-scale synthesis of other metal phosphides.

A convenient and one-pot approach to prepare [1,2,3]triazolo[1,5-a]quinoxalin-4(5H)-ones by a metal-free sequential Ugi-4CR/alkyne–azide cycloaddition reaction has been developed. The reaction of 2-azidobenzenamines, aldehydes, propiolic acids, and isocyanides produced the Ugi adducts, which were transformed to the [1,2,3]triazolo[1,5-a]quinoxalin-4(5H)-ones in moderate to good yields via alkyne–azide cycloaddition reaction.

Leaves of Conocarpus erectus are potential feedstock for bioethanol production due to their lower lignin and higher cellulosic content and are among one of the least explored biomass sources. The present study reported a low-temperature (90 °C) energy-efficient pretreatment method for the release of fermentable sugars from C. erectus leaves and its conversion into bioethanol by using industrial and lab yeast strains. Optimization of process parameters was performed by monitoring glucose utilization and ethanol production. The maximum glucose concentration of 12 g L−1 and 19.75 g L−1 were obtained after the low-temperature (90 °C) pretreatment and enzymatic saccharification, respectively. The optimum enzymatic assay conditions were with 10% biomass and enzyme loading of 30 FPU/g cellulose, resulting in the release of ~ 20 g L−1 of glucose from pretreated biomass which is equivalent to the glucose concentration in standard growth media. Hydrolysate fermentation by S. cerevisiae strains SPSC01, ER, YB2625, and 6525 exhibited highest ethanol yields of 0.47 g g−1 and 0.46 g g−1 which is the highest ever reported for C. erectus even under acetic acid stress, where a fermentation efficiency of 92.3% was achieved. The present study may lead to establishing low-cost, energy-efficient biological conversion of C. erectus to ethanol.

Adjusting the charge environment and charge transfer to optimize the hydrogen absorption free energy (ΔGH*) is an effective strategy to improve the intrinsic activities of electrocatalysts toward t...

Developing low-cost and high performance catalysts for oxygen evolution reaction (OER) is a vital way to promote the effective cost and industrial applications of water splitting. In this work, we synthesize the hierarchical structure of NiFe(OH)x/VS/NF nanosheets using vanadium sulfide (VS) layer coating on the nickel foam (NF) as substrate. VS on the surface of NF can make effect on the distribution and morphology of NiFe(OH)x. The vertical NiFe(OH)x nanosheets supported VS/NF can not only provide abundant active sites for OER but also have the advantages of excellent conductivity substrate. The three dimensional skeleton structure of NF can also faster oxygen diffusion process, which suggests outstanding electrocatalytic activity in alkaline medium. Employing it for water splitting with a current density of 200 mA cm−2 is achievable at a low voltage of 1.506 V vs. RHE with remarkable long-term stability. Moreover, the synergistic hybridization of layered VS/NF with layered double hydroxides (LDH) materials enlightens the design and fabrication of promising hybrid materials. This work may offer a viable route to design the advanced electrode materials for OER electrocatalysts.

Transition metal hydroxides for hydrogen evolution reaction (HER) usually have been limited by poor intrinsic activity and weak conductivity. In our work, in situ electro-oxidation as an effective way has been used to modulate the electronic states of active sites for ruthenium hydroxides, which provides obviously enhanced activity for HER in alkaline media. Ag-modified nickel foam (NF) as substrate can provide the excellent conductivity to improve the charge transfer rate of Ru(OH)x/Ag/NF. In situ electro-oxidation process has been conducted for Ru(OH)x/Ag/NF through OER measurements in alkaline media, which results in the formation of more Ru (IV) as higher actives sites for HER. Compared to Ru(OH)x/NF, X-ray photoelectron spectroscopy (XPS) and polarization curves prove that Ag doping in Ru(OH)x/Ag/NF may contribute to the oxidization of ruthenium from Ru (III) to Ru (IV) during in situ electro-oxidation. The obtained Ru(OH)x/Ag/NF exhibits Pt-like HER activity with a very low overpotential of 103.2 mV to drive 100 mA cm−2 in 1.0 M KOH. The excellent stability of Ru(OH)x/Ag/NF has also been demonstrated. Therefore, our work provides a new strategy by modulating valence state of active sites for transition metal hydroxides for efficient HER.

In recent times, the fabrication of versatile mesoporous silica walls by incorporating various metal species has attracted enormous interest as they significantly enrich the functionalities of mesoporous silica nanoparticles (MSNs) by offering numerous advantages in diverse fields. Herein, we demonstrate the generation of mesoporous silica-based, dual-metal doped, biodegradable Janus-type (sphero-ellipsoid) nanoreactors using modified Stober process by arranging two different transition metals in the silica walls, which facilitated the change of MSN’s shape, attributing to their similar charge as well as the distribution of intrinsic siliceous bonds in the confined architectures. As a proof-of-concept, the doped metal species in the silica walls have significantly augmented the loading efficiency of doxorubicin (Dox) through pH-responsive metal-ligand interactions, which specifically released Dox in the tumor endosomal acidic environment and synergized the antitumor efficacy by augmenting the intracellular levels of cytotoxic reactive oxygen species (ROS) through copper/iron(II)-catalyzed Fenton-like reaction. This innovative one-step approach for synthesizing Janus-type nanoreactors would be a conducive strategy and has great potential as a delivery system in diverse biomedical applications for treating various ailments. We also believe that the nanodevices in association with metals resulting in different shapes could significantly alter the therapeutic effects.

It is essential to make sure patients be actively involved in motor training using robot-assisted rehabilitation to achieve better rehabilitation outcomes. This paper introduces an attention-controlled wrist rehabilitation method using a low-cost EEG sensor. Active rehabilitation training is realized using a threshold of the attention level measured by the low-cost EEG sensor as a switch for a flexible wrist exoskeleton assisting wrist flexion/extension and radial/ulnar deviation. We present a prototype implementation of this active training method and provide a preliminary evaluation. The feasibility of the attention-based control was proven with the overall actuation success rate of 95%. The experimental results also proved that the visual guidance was helpful for the users to concentrate on the wrist rehabilitation training: two types of visual guidance, namely, looking at the hand motion shown on a video and looking at the user's own hand had no significant performance difference. A general threshold of a certain group of users can be utilized in the wrist robot control rather than a customized threshold to simplify the procedure.

Designing nanosized and hierarchically porous zeolite with intracrystalline mesopores can enhance mass transport ability to improve the catalytic performance of HPPO, which is of prime scientific and industrial importance. Nanosized titanium silicalite-1 (TS-1, 360 × 190 × 640 nm) was first synthesized in a tetrapropylammonium bromide (TPABr)-n-butylamine dry gel system using the seed-assisted method, and post-modification with pure ammonium fluoride (NH4F) solution. This strategy introduced uniform intracrystalline mesoporosity and increased the hydrophobicity. Reducing the TS-1 grain size and creating a hierarchical porous architecture can improve the diffusion of molecules. This solves challenges in mass transport and promotes the catalytic performance. This catalyst was used for propylene epoxidation. The conversion of hydrogen peroxide and selectivity of propylene oxide (PO) attained 98.4% and 97.6%, respectively. Even after 5 runs, the catalyst still maintained a stable performance after simple filtering.

As a cost-effective element, Mg has been applied as doped inactive atom to improve the electrochemical performance of sodium-ion cathode materials. Herein, we report Mg-substituted Na0.67Mn0.65Ni0.2Co0.15-xMgxO2 composites as high-performance cathode for sodium-ion batteries and investigate the underlying working mechanism using in situ investigation techniques to monitor the operando changes of electrodes. In situ X-ray diffraction investigation demonstrates P2-type structure is well preserved even charged to 4.3 V and the changes of lattice parameters and unit cell volume of Na0.67Mn0.65Ni0.2Mg0.15O2 are alleviated via Mg replacement. As a result, the capacity retention increases from 62% in Na0.67Mn0.65Ni0.2Co0.15O2 to 94% in Na0.67Mn0.65Ni0.2Mg0.15O2. Meanwhile, less CO2 evolution was detected in the coin cell with Na0.67Mn0.65Ni0.2Mg0.15O2 electrode than in that with Na0.67Mn0.65Ni0.2Co0.15O2 electrode in online differential electrochemical mass spectrometry test, suggesting a depressed side reaction between electrode and electrolyte after Mg completely replacing Co. In situ electrochemical impedance spectroscopy investigation further proves Mg is beneficial for the interfacial conductivity enhancement compared to Co, which provides evidence for enhanced high rate capabilities. These comprehensive results provide new viewpoints to explain the improved cycling and rate capabilities from the aspects of crystal structure evolution, coin cell gas evolution and electrolyte/electrode interface conductivity during charge/discharge process.

Ultrafine Ni2P/Co2P nanoparticles encapsulated in hollow porous N-doped carbon nanospheres are synthesized through a facile two-step access. Firstly, metallic Ni and Co coated by hollow N-doped spheres as precursors are obtained through a high temperature calcination route of organic polymer and inorganic Ni and Co salts. Then bimetal Ni2P/Co2P supported on N-doped carbon nanospheres are acquired by a facile phosphorization process. It is worth to note that aniline-pyrrole polymer can prevent fast growth and severe aggregation of Ni2P/Co2P, which implies more exposed active sites. Moreover, the calcination of hollow polymer spheres lead to the formation of ultrathin NC shell on the surface of Ni2P/Co2P hybrids, which can tune electronic structures, improve the conductivity and protect active sites from corrosion in harsh conditions. When used as HER catalyst, it displays remarkable catalytic activity in both acidic and alkaline solutions, which needs an onset potential of only 164 mV and 168 mV, respectively. Therefore, this work may propose a new strategy to design unique inorganic-organic heterostructures to combine ultrafine metal phosphides with porous carbon for efficient HER.

The ultrathin MoS2 nanosheets-coated N, P dual-doped hollow carbon nanospheres (NPC@MoS2) have been synthesized through a facile template sacrificial method to prepare P-promoted enlarged hollow carbon spheres with followed solvothermal process. P doping in NC can not only tune the electron configuration but also promote formation of hollow nanospheres with larger voids compared with NC. The key to producing carbon spheres with larger voids can be ascribed to the rapid oxidation of P species at high temperature, which provides a strong driving force for the outward diffusion of P. Through optimizing the amount of Mo source, the as-prepared NPC@MoS2 with medium amount of Mo source have demonstrated outstanding hydrogen evolution performance with a small overpotential of 178 mV at a current density of 10 mA cm−2 and maintain stable in acidic solution. This superior performance is attributed to the unique nanostructures with N, P dual-doped conductive carbon spheres with highly hollow degree as core and well-dispersed MoS2 nanosheets as shell. Therefore, this work suggests that choosing carbon matrix with large surface area as support is the key to synthesizing MoS2-based electrocatalysts with enhanced HER activity.

Lignocellulosic biomass is a sustainable feedstock for fuel ethanol production, but it is characterized by low mass and energy densities, and distributed production with relatively small scales is more suitable for cellulosic ethanol, which can better balance cost for the feedstock logistics. Lignocellulosic biomass is recalcitrant to degradation, and pretreatment is needed, but more efficient pretreatment technologies should be developed based on an in-depth understanding of its biosynthesis and regulation for engineering plant cell walls with less recalcitrance. Simultaneous saccharification and co-fermentation has been developed for cellulosic ethanol production, but the concept has been mistakenly defined, since the saccharification and co-fermentation are by no means simultaneous. Lignin is unreactive, which not only occupies reactor spaces during the enzymatic hydrolysis of the cellulose component and ethanol fermentation thereafter, but also requires extra mixing, making high solid loading difficult for lignocellulosic biomass and ethanol titers substantially compromised, which consequently increases energy consumption for ethanol distillation and stillage discharge, presenting another challenge for cellulosic ethanol production. Pentose sugars released from the hydrolysis of hemicelluloses are not fermentable with Saccharomyces cerevisiae used for ethanol production from sugar- and starch-based feedstocks, and engineering the brewing yeast and other ethanologenic species such as Zymomonas mobilis with pentose metabolism has been performed within the past decades. However strategies for the simultaneous co-fermentation of pentose and hexose sugars that have been pursued overwhelmingly for strain development might be modified for robust ethanol production. Finally, unit integration and system optimization are needed to maximize economic and environmental benefits for cellulosic ethanol production. In this article, we critically reviewed updated progress, and highlighted challenges and strategies for solutions.

Lithium (Li) metal is a favorable anode for most energy storage equipment, thanks to its higher theoretical specific capacity. However, nonuniform Li nucleation/growth results in large-sized and irregular dendrites generated from the Li anode, which causes rapid capacity fade and serious safety hazard, hindering its widespread practical applications. In this paper, with the aid of a lithium nitrate (LiNO

The exploration of low-cost, stable, and highly active noble-metal-free electrocatalyst for hydrogen evolution reaction (HER) in a wide pH range is crucial but still challenging task for renewable energy techniques. MoS2-based materials have been considered as a promising electrocatalyst for HER. However, corresponding studies have been hampered by the lack of effective routes to fully utilize the large number of inert basal plane for catalyzing HER, especially under alkaline media. Herein, a novel ammonia ions-guided-nitrogenization-phosphorization strategy is developed to prepare N and P co-doped MoS2 with active basal plane for efficient catalyzing HER with a quite low overpotential of 116 and 78 mV in 0.5 M H2SO4 and 1.0 M KOH to achieve a current density of 10 mA cm−2, respectively. Experimental studies and theoretical calculations confirm Mo-N-P sites in the basal plane of MoS2 can not only accelerate HER kinetics, but also result in energetic favorability and structure stability. Furthermore, outstanding performances are also obtained under both sea and river water, vastly broadening the application prospects.

In this work, a series of NixCo1−xSe2 selenides are prepared with x ranging from 0 to 1 and investigated as electrode materials for supercapacitor. The sample Ni0.6Co0.4Se2 shows 1580 and 1205 F g−1 at 1 and 20 A g−1, respectively. At 10 A g−1, 90% capacitance retention is sustained after 20,000 cycles. A Ni0.6Co0.4Se2-based asymmetric supercapacitor (ASC) is assembled and exhibits energy density of 44.1 and 36.8 Wh kg−1 at power density of 691.3 and 15070.6 W kg−1 and long stability. Systematic physicochemical/electrochemical analysis reveals that the high active MOOH (M = Ni, Co)/Ni0.6Co0.4Se2 phases generated by electrooxidation act as the actual active materials during the charge storage/release process. The collective effects of large ion-accessible active area, high conductivity and electrochemically active MOOH (M = Ni, Co)/Ni0.6Co0.4Se2 phases convincingly account for the remarkable performance, especially the excellent rate capability and stability.

Designing a unique electrochemical interface to exhibit Pt-like activity and good stability is indispensable for the efficient hydrogen evolution reaction (HER). Herein, we synthesize well-defined Mo2C@NC@Pt nanospheres with a sandwich-structured interface through a facile organic-inorganic pyrolysis and following reduction process. The obtained Mo2C@NC@Pt heterostructures with ultralow Pt loading are composed of well-dispersed Mo2C nanoparticles (NPs) inner layer, N-doped carbon layer, and ultrafine Pt NPs outer layer. Electrochemical measurements demonstrate that Mo2C@NC@Pt heterostructures not only exhibit superior HER activities than commercial Pt/C with small overpotentials of only 27, 47, and 25 mV to achieve a current density of 10 mA cm-2 in acidic, alkaline, and neutral media, respectively, but also possess favorable long-term stability in pH-universal solution. The improved reaction kinetics of Mo2C@NC@Pt heterostructures are mainly attributed to the unique sandwich-structured interface with well-defined Mo2C NPs encapsulated by carbon layers and Pt NPs well-dispersed on the carbon support, synergistic effects among Mo2C NPs, NC, and Pt NPs, high specific surface area, and N-doping into the catalysts. This facile approach not only provides a new pathway for preparing well-defined carbides but also gives insight into the development of low-Pt catalysts for the efficient HER.

We report an electrochemical protocol for the direct oxidation of internal alkynes in air to provide 1,2-diketones. A variety of functional groups and heterocycle-containing substrates can be tolerated well under mild conditions.

Improving the cementitious activity and volume stability of steel slag by thermal reconstruction is an innovative method for efficient utilization of steel slag. In this study, different amounts of CaF2 and CaSO4 were added to steel slag as a mineralizer based on the determining admixtures needed for the reconstruction reaction, and the effects of CaF2 and CaSO4 on the cementitious activity and volume stability of the reconstructed steel slag were investigated. The results show that when the CaF2 content is increased to 5 wt%, the cementitious activity index of the reconstructed steel slag gradually increases to 92%, which is 12% higher than the first level technical requirement specified by the national standards, and the free CaO (f - CaO) and MgO (f-MgO) contents gradually decrease to 0.35 and 0.13 wt%, respectively. With increasing CaSO4 content, the cementitious activity index first increases and then decreases, while the contents of f -CaO and f-MgO show the opposite trend. When the CaSO4 content is 2 wt%, the activity index is 105%,which is 25%higher than the first level technical requirement specified by the national standards, and the f -CaO and f-MgO contents reach minima of 0.44 and 0.35 wt%, respectively.

An unsupported Ni Mo catalyst was modified by β-zeolite nanoclusters synthesized by the hydrothermal method. The effect of the nanoclusters on the acidity of unsupported catalyst was studied. Results showed that the Lewis acid and the total acid amount of the unsupported catalyst were improved. Indicating that the β-zeolite nanoclusters was successfully introduced into the unsupported catalyst. And the catalytic activity results showed that the introduction of β-zeolite nanoclusters not only led to the higher desulphurization and isomerization activity, but also improved the ratio of direct desulfurization paths (DDS), which is in favor of reducing hydrogen consumption.

Diabetes mellitus is one of the most common noncommunicable diseases in the world. Fasting blood glucose level is one of the diabetes diagnostic criteria, but it is readily affected by stress, exercise and many other factors. Glycated hemoglobin (HbA1c) is an important clinical index for diabetes and related diseases. In this study, a cheaper, rapid-prototyping, high-sensitivity angle-scanning surface plasmon resonance (SPR) was developed by fused deposition modeling (FDM) 3D printing technology for HbA1c detection. The sensor chip is based on an aptamer that has high affinity and high specificity to HbA1c. The results showed that this HbA1c-specific aptamer had high specificity for HbA1c, and the calculated KD was 6.13 × 10−8 M. The linear detection response of HbA1c appeared in the range of 18–147 nM, with a detection limit of 1 nM. This SPR HbA1c detection system could be a promising platform for developing clinical point-of-care diagnostic applications.

To investigate the essential role of H2 on thiophene removal over supported nickel catalysts, a NiO/Al2O3 catalyst was prepared, and a series of desulfurization reactions were carried out with different H2 feed concentrations. The characterization of fresh and spent catalysts indicated that reduced nickel (Ni0), which showed dependence on the H2 feed concentration, was the key factor to the thiophene reactive adsorption desulfurization (RADS) process. The equilibrium between sulfurization and reduction of nickel species retained the activity of the catalyst. The stability of the formed nickel sulfides was related to the H2 feed concentration. The higher H2 feed concentration favored the RADS process for the positive auto-regeneration of the nickel species.

Microwave is widely used to synthesize advanced nanomaterials for energy storage and conversion, whereas its applications remain limited in water electrolysis. Herein, we qualitatively explore the house-hold microwave annealing in atmosphere as chemical-free oxidation pretreatment strategy on Ni 3 S 2 nanowires for hydrogen evolution reaction (HER). The microwave can induce fast surface oxidation to form metal hydroxides on catalyst which promotes in-situ electrochemical activation (ISEA) to improve the catalytic performance. The microwave annealing is superior to traditional oxidation such as chemical oxidation or Ar gas annealing. Thanks to faster reaction kinetics, better conductivity and larger electrochemical surface area, the formed NiO x /Ni 3 S 2 hybrids by ISEA achieve 7-time higher activity and operate well for 12 h compared with pristine catalyst. The NiO x /Ni 3 S 2 hybrids also perform well in acid (0.5 M H 2 SO 4 ) and neutral (1.0 M phosphate buffer solution) media to realize all-pH water electrolysis. Moreover, the microwave annealing is found to be applicable for other transition metals such as cobalt sulfide to obtain higher HER properties. Therefore, such chemical-free modulation concept in our work might be a general access for many advanced materials in other electrocatalysis fields.

Though solar cells are one of the promising technologies to address the energy crisis, this technology is still far from commercialization. Thermoelectric materials offer a novel opportunity to convert energy between thermal and electrical aspects, which show the feasibility to improve the performance of solar cells via heat management and light harvesting. Polymer–inorganic thermoelectric nanocomposites consisting of inorganic nanomaterials and functional organic polymers represent one kind of advanced hybrid nanomaterials with tunable optical and electrical characteristics and fascinating interfacial and surface chemistry. During the past decades, they have attracted extensive research interest due to their diverse composition, easy synthesis, and large surface area. Such advanced nanomaterials not only inherit low thermal conductivity from polymers and high Seebeck coefficient, and high electrical conductivity from inorganic materials, but also benefit from the additional interface between each component. In this review, we provide an overview of interfacial chemistry engineering and electrical feature of various polymer–inorganic thermoelectric hybrid nanomaterials, including synthetic methods, properties, and applications in thermoelectric devices. In addition, the prospect and challenges of polymer–inorganic nanocomposites are discussed in the field of thermoelectric energy.

In recent years, the fabrication of smart materials at an arbitrary gauge has attracted enormous interest from researchers in the tissue engineering (TE) field. This potential tool has been utilized for the generation of various biomimetic/bioinspired structures to repair and improve the performance of the injured tissues. Cardiac TE is one of them that offers immense benefits in treating various cardiovascular diseases, such as myocardial infarction (MI). Currently, various nanoparticles have been utilized alone or by incorporating them in hydrogels or other biomimetic scaffolds to mimic the morphological and electrophysiological characteristics of native cardiac tissue for a better regenerative outcome. Herein, we aim to give a brief overview, which provides an emphasis and discussion of the latest reports on these innovative nanoconstructs intended for cardiac TE. Finally, we summarize the existing challenges and prospects of the cardiac TE field.

The development of high activity electrocatalysts that can operate stably at high current density for the large-scale production of hydrogen is an important but challenging task. Herein, we report a simple method for constructing F, P double-doped Fe3O4 with abundant defect sites for hydrogen evolution reaction (HER) on iron foam (F, P-Fe3O4/IF). Significantly, the obtained F, P-Fe3O4/IF showed great HER catalytic activity in high- and low-concentration alkaline electrolyte solutions. To drive 100 mA cm−2, it only required the overpotentials of 179.5 and 149.4 mV in 1 M and 6 M KOH solutions, respectively. Furthermore, the long-time stability test indicated that F, P-Fe3O4/IF lasted for more than 12 h at various high current densities (500, 1000 and 2000 mA cm−2), which revealed its great potential in the water electrolysis industry. Density functional theory (DFT) calculations revealed that doping with F and P could effectively optimize the electronic structure of Fe3O4, thus lowering the hydrogen adsorption energy. This work provides a unique strategy of utilizing elements with different electronegativities for doping to improve the HER performance of iron oxides.

The present study was focused on evaluating the bioenergy potential of waste biomass of desert plant Calotropis procera. The biomass was pyrolyzed at four heating rates including 10 °Cmin−1, 20 °Cmin−1, 40 °Cmin−1, and 80 °Cmin−1. The pyrolysis reaction kinetics and thermodynamics parameters were assessed using isoconversional models namely Kissenger-Akahira-Sunose, Flynn-Wall-Ozawa, and Starink. Major pyrolysis reaction occurred between 200 and 450 °C at the conversion points (α) ranging from 0.2 to 0.6 while their corresponding reaction parameters including activation energy, enthalpy change, Gibb’s free energy and pre-exponential factors were ranged from 165 to 207 kJ mol−1, 169–200 kJ mol−1, 90–42 kJ mol−1, and 1018–1026 s−1, respectively. The narrow range of pre-exponential factors indicated a uniform pyrolysis, while lower differences between enthalpy change and activation energies indicated that reactions were thermodynamically favorable. The evolved gases were dominated by propanoic acid, 3-hydroxy-, hydrazide, hydrazinecarboxamide and carbohydrazide followed by amines/amides, alcohols, acids, aldehydes/ketones, and esters.

In recent times, the combination therapy has garnered enormous interest owing to its great potential in clinical research. It has been reported that disulfiram, a clinical antialcoholism drug, could be degraded to diethyldithiocarbamate (DDTC) in vivo and subsequently result in the copper-DDTC complex (Cu(DDTC)2) toward ablating cancer cells. In addition, the ultrasmall copper sulfide nanodots (CuS NDs) have shown great potential in cancer treatment because of their excellent photothermal and photodynamic therapeutic efficiencies. Herein, by taking advantage of the interactions between CuS and DDTC, a new multifunctional nanoplatform based on DDTC-loaded CuS (CuS-DDTC) NDs is successfully fabricated, leading to the achievement of the synergistic effect of photothermal and copper enhanced chemotherapy. All experimental results verified promising synergistic therapeutic effects. Moreover, in vivo biocompatibility and metabolism experiments displayed that the CuS-DDTC NDs could be quickly excreted from the body with no apparent toxicity signs. Together, our findings indicated the superior synergistic therapeutic effect of photothermal and copper-enhanced chemotherapy, providing a promising anticancer strategy based on the CuS-DDTC NDs drug delivery system.

The overdeveloped lysosomes in cancer cells are gaining increasing attention toward more precise and effective organelle-targeted cancer therapy. It is suggested that rod/plate-like nanomaterials with an appropriate size exhibited a greater quantity and longer-term lysosomal enrichment, as the shape plays a notable role in the nanomaterial transmembrane process and subcellular behaviors. Herein, a biodegradable platform based on layered double hydroxide-copper sulfide nanocomposites (LDH-CuS NCs) is successfully prepared via in situ growth of CuS nanodots on LDH nanoplates. The as-prepared LDH-CuS NCs exhibited not only high photothermal conversion and near-infrared (NIR)-induced chemodynamic and photodynamic therapeutic efficacies, but also could achieve real-time in vivo photoacoustic imaging (PAI) of the entire tumor. LDH-CuS NCs accumulated in lysosomes would then generate extensive subcellular reactive oxygen species (ROS) in situ, leading to lysosomal membrane permeabilization (LMP) pathway-associated cell death both in vitro and in vivo.

Compared with traditional lithium-ion systems, solid-state batteries could achieve high safety and energy density. Although great improvements have been made, especially in solid-state electrolytes, fundamental challenges still remain for the solid-state systems in terms of chemistry and mechanics. This review summarizes the fundamental issues in solid-state batteries with a focus on three critical phenomena: (i) the principles of developing high ionic conductors, (ii) structural evolution at chemically unstable electrolyte-electrode interfaces, and (iii) the effects of manufacturing solid-state batteries, including electrode, and electrolyte design. The future perspectives are also outlined to guide the development of solid-state batteries.

Background Microbial fuel cell (MFC) convokes microorganism to convert biomass into electricity. However, most well-known electrogenic strains cannot directly use glucose to produce valuable products. Zymomonas mobilis, a promising bacterium for ethanol production, owns special Entner–Doudoroff pathway with less ATP and biomass produced and the low-energy coupling respiration, making Z. mobilis a potential exoelectrogen. Results A glucose-consuming MFC is constructed by inoculating Z. mobilis. The electricity with power density 2.0 mW/m2 is derived from the difference of oxidation–reduction potential (ORP) between anode and cathode chambers. Besides, two-type electricity generation is observed as glucose-independent process and glucose-dependent process. For the sake of enhancing MFC efficiency, extracellular and intracellular strategies are implemented. Biofilm removal and addition of c-type cytochrome benefit electricity performance and Tween 80 accelerates the electricity generation. Perturbation of cellular redox balance compromises the electricity output, indicating that redox homeostasis is the principal requirement to reach ideal voltage. Conclusion This study identifies potential feature of electricity activity for Z. mobilis and provides multiple strategies to enhance the electricity output. Therefore, additional electricity generation will benefit the techno-economic viability of the commercial bulk production for biochemicals or biofuels in an efficient and environmentally sustainable manner.

A chemical investigation of the whole plant of traditional Chinese medicine, Chrysanthemum indicum L., led to the discovery of six guaianolide-type sesquiterpenoids 1–6 with a 1,10-splited skeleton. The structure of the new compound 1 was established by extensive analysis of UV, IR, MS, NMR and ECD data. Compounds 3–6 are mutually stereoisomers with four chiral centers and their absolute configurations were determined by comparison of ECD spectra. The anti-inflammatory effects of these isolates on lipopolysaccharide (LPS)-induced nitric oxide (NO) were investigated in RAW 264.7 cells. Results showed that most of the compounds displayed NO production inhibitory activities with IC50 values ranged from 3.54 to 8.17 μM.

Three-dimensional (3D) Na2Ti6O13 microflowers assembled from directionally arranged and closely interlinked one-dimensional N-doped carbon Na2Ti6O13 nanorods have been successfully prepared by a self-sacrificed template method followed by sintering in argon. In situ high-temperature X-ray powder diffraction (XRD) characterization was conducted to explore the phase transformation and structural evolution. The results indicated that the NaTi3O6(OH)·2H2O precursor was converted into the tunnel Na2Ti6O13 phase and the layered Na2Ti3O7 phase at the different temperatures. At a certain temperature, the tunnel and layered phases have a mutual transformation. The higher temperature was not conductive to the formation of pure phases. The crystal structural evolution has been given based on the synthesis process and in situ high temperature XRD patterns. When served as anode for SIBs, a capacity of ca. 30 mAh g–1 over 6000 continuous cycles was retained at 2000 mA g–1. Moreover, the structural and morphology integr...

Adsorption method was first introduced into the propene oxide production via hydrogen peroxide process to remove the microimpurity in the propylene oxide (PO) product solution. It could replace the reactive distillation in separating acetaldehyde with less energy consumption and PO loss. A series of adsorbents (e.g., 3A, 4A, 5A, 10X, and Y) are first used to remove the impurity (i.e., acetaldehyde). It is found that 5A molecular sieves shows the best performance due to uniform porous channels with suitable pore size. Various techniques such as X-ray diffraction, scanning electron microscopy, thermogravimetric analysis, Fourier transform infrared, and N2 physisorption are employed to investigate the structural properties of the adsorbent. Furthermore, effects of space velocity and temperature are also investigated. Cyclic desorption and adsorption tests indicate the PO yield is 92.2%, and 96.3% of acetaldehyde was removed. The acetaldehyde concentration of PO product was 0.0187%, indicating this method can produce industrial-quality PO that meets the first-level technical requirements.