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The biggest obstacles of putting lithium-sulfur batteries into practice are the sluggish redox kinetics of polysulfides and serious "shuttle effect" under high sulfur mass loading and lean-electrolyte conditions. Herein, Fe3C/Fe3N@nitrogen-doped carbon nanotubes (NCNTs) as multifunctional sulfur hosts are designed to realize high-areal-capacity Li-S batteries. The Fe3N and Fe3C particles attached to NCNT can promote the conversion of polysulfides. Besides, NCNT can not only enhance the chemisorption of polysulfides but also increase the special surface area and electrical conductivity by constructing a three-dimensional skeleton network. Integrating the merits of high electrical conductivity, high catalytic activity, and strong chemical binding interaction with lithium polysulfides (LiPSs) to achieve in situ anchoring conversion, the Fe3C/Fe3N@NCNT multifunctional hosts realize high sulfur mass loading and accelerate redox kinetics. The novel Fe3C/Fe3N@NCNT/S composite cathode exhibits steady cycle ability and a high areal capacity of 9.10 mAh cm-2 with a sulfur loading of 13.12 mg cm-2 at 2.20 mA cm-2 after 50 cycles.

Temporally intermittent and spatially dispersed renewable energy sources strongly call for large-scale energy storage devices. Aqueous aluminum-ion batteries show great potential for application du...

Electro- and photocatalytic hydrogen evolution reaction (e-HER and p-HER) are two promising strategies to produce green hydrogen fuel from water. High intrinsic activity, sufficient active sites, fast charge-transfer capacity, and good optoelectronic properties must be taken into consideration simultaneously in pursuit of an ideal bifunctional catalyst. Here, platinum atomic clusters embedded in defects of TiO2 nanocrystals/graphene nanosheets (Pt-T/G) are reported as a bifunctional catalyst for electro- and photocatalytic hydrogen evolution reaction (e-HER and p-HER). High activity is delivered due to the charge transfer from the other part of the catalyst to the active center (Pt2-O4-Tix), decreasing the activation energy of the rate-limiting step, which is revealed by synchrotron X-ray absorption spectroscopy, photoelectrochemical measurements, and simulated calculations. In regard to e-HER, it outperforms the commercial 20 wt % Pt/C catalyst by a factor of 17.5 on Pt mass basis, allowing for a 93% reduction in Pt loadings. In regard to p-HER, it achieves photocatalytic efficiency (686.8 μmol h-1) without any attenuation in 9 h.

Water splitting by electrolysis is a promising technology that can address rising energy demands and environmental pollution. However, the oxygen evolution reaction (OER), as one half-cell reaction of water splitting, always suffers from slow kinetics and a large overpotential due to the four proton-coupled electron transfer process, and dominates the overall process efficiency. IrO2 is a promising and widely used catalyst for the OER in commercial applications. Herein, we obtained low-crystalline nano-IrO2 particles confined in an amorphous Ir-based MOF (IrO2@Ir-MOF) through a simple solvothermal reaction, in which ultrafine IrO2 particles are uniformly distributed in the Ir-MOF skeleton. The fabricated IrO2@Ir-MOF-ppy electrode exhibits excellent OER activity with an overpotential of 207 mV, to achieve a current density of 10 mA cm−2 in 1 M KOH solution, outperforming most previously reported OER catalysts. The IrO2@Ir-MOF‖IrO2@Ir-MOF couple exhibits promising activity and stability for the overall water splitting reaction in 1 M KOH (1.53 V).

In mining industries, the backfill becomes more and more important due to the environment protection concern. But most backfill investigations focus on the underground model and backfill materials. In this research, the paste backfill process based on the process control is investigated and a new paste backfill process model is proposed according to the Torricelli's law and Bernoulli principle. In order to deal with the unknown nonlinear function of the proposed backfill model, a Petri net(PN) structure is presented and a new Petri net neural network(PNNN) is introduced to approximate the unknown nonlinear function. Then, a robust controller is designed for the backfill process with PNNN and the closed loop stability is guaranteed by Lyapunov function candidate. The effectiveness of the proposed model with new PNNN and the robust controller are verified by simulation results.

Hydrogen evolution reaction (HER) is a crucial half-reaction of water splitting to produce possible future energy carrier: H2, which is directly associated with the conversion and storage of clean energy. There is a great demand on efficient earth-abundant electrocatalysts to replace Pt, especially in alkaline medium. Herein, we report Co2Ni alloy anchored on nitrogen-doped carbon nanotubes (Co2Ni alloy/N-CNTs) as an efficient alkaline HER electrocatalyst. The alloy is prepared from a straightforward hydrothermal reaction and a post-annealing process in NH3 atmosphere, which in situ reduces the nickel cobalt carbonate hydroxide precursor to alloy and brings N-doping to CNTs without changing original morphology. The as-obtained Co2Ni alloy/N-CNTs hybrids exhibit superior alkaline HER performance with a small Tafel slope of 87 mV dec−1, high exchange current density of 0.8 mA cm−2 and a low overpotential of 100 mV to drive current density of 10 mA cm−2, which is comparable to commercial Pt/C and surpasses numerous reported earth-abundant electrocatalysts. This electrocatalyst can also endure long-time HER process (>24 h). The excellent catalytic performance can be attributed to accelerated charge transfer, more exposed active sites and structural robustness which all benefit from the structural and component configuration that brought by alloy and N-doped CNTs.

It is vital to develop oxygen evolution reaction catalyst with rational designed composition and microstructure to facilitate the overall electrochemical water splitting. In this work, uniform NixFe1-x-P nanosheets arrays are vertically grown on carbon cloth to form an effective oxygen evolution reaction catalyst. Such structure is prepared by phosphorization of the corresponding layered double hydroxide nanosheets. In this synthesis, the hydroxides are converted to phosphide while the porous nature is well retained. The ratio of Ni to Fe in the phosphide is tuned and the optimized synergistic effect between Ni and Fe for oxygen evolution reaction catalytic activity is achieved. The nanoarrays with hierarchical porous structure offer more reaction sites and promote the charge transfer. As a result, low reaction overpotential and small Tafel slope have been realized. In additional, the synthesis strategy can be also applied to prepare Ni5P4 hydrogen evolution reaction catalyst. A full water electrolyzer is demonstrated with the optimized cathode and anode, and remarkable overall water splitting activity is obtained with a current density of 10 mA cm−2 at the potential of 1.53 V.

The paste backfill mining becomes more important since the urgency of the reducing pollution, saving energy and improving technology in the mining. Most researches focus on the paste material itself but are not interested in the paste backfill process model. Considering of the importance for the paste backfill mining, the paste backfill process model is developed based on the centrifugal pump model and the permanent magnet synchronous motor(PMSM) model in this paper. In the real paste backfill process, the centrifugal pump is driven by the PMSM as a holistic system. Then, the unitary paste backfill process model is proposed including the PMSM driving the pump and a PID controller is designed to verify the effectiveness of the proposed paste backfill process model. Simulations demonstrate the proposed paste backfill model feasible.

Owing to the excellent abundance and availability of sodium reserves, sodium ion batteries (NIBs) show great promise for meeting the material supply and cost demands of large-scale energy storage systems (ESSs) used for the application of renewable energy sources and smart grids. However, the cost advantages of stationary NIBs alone are not enough to ensure their commercial success. In this review, we summarize the emerging attractive characteristics of stationary NIBs, such as high-rate capability, all-climate operation, and full-battery recyclability. Together with inherent cost advantages, these merits have resulted in an excellent compatibility between stationary NIBs and large-scale ESSs that dictates their validity in practical applications. Representative electrode materials are highlighted to illustrate advances in corresponding features. The insights presented in this review can inspire further research interest into NIB design and serve as a guide for the application of NIBs in large-scale stationary energy storage.

The low electronic conductivity of sulfur and the diffusion and shuttle of polysulfide intermediates are the main obstacles of the cathode that restrain the progress of lithium–sulfur (Li–S) batteries. To address the two main predicaments, we explored a dual functional 3D hierarchical filter element structured Mo2C nanosheet based sulfur electrode. The Mo2C based sulfur electrodes fulfill the requirements of conductivity (30 S cm−1) and entrapment of diffusing polysulfide intermediates, and meanwhile possess the advantages of high crystallinity and large specific surface area. As a filter and reservoir for polysulfides, Mo2C nanosheets possess a strong chemical interaction with polysulfides to mitigate the shuttling of polysulfides. The dual functional Mo2C nanosheet based electrode exhibited a high initial discharge capacity of ca. 1200 mA h g−1 and ca. 800 mA h g−1 after 300 cycles at 0.2C. Moreover, the flexibility of the sulfur electrode is explored through an in situ fabrication on carbon cloth in a soft-package configuration.

This work reports the synthesis of coaxial carbon@NiMoO4 nanofibers for supercapacitor electrode applications. Thin NiMoO4 nanosheets are uniformly coated on the conductive electrospun carbon nanofibers by a microwave assisted hydrothermal method to form a hierarchical structure, which increases the porosity as well as the conductivity of the electrode. The thickness of the NiMoO4 can be easily adjusted by varying the precursor concentrations. The high specific surface area (over 280 m2 g−1) and conductive carbon nanofiber backbone increase the utilization of the active pseudocapacitive NiMoO4 phase, resulting a high specific capacitance of 1840 F g−1.

The shuttle effect hinders the practical application of lithium-sulfur (Li-S) batteries due to the poor affinity between a substrate and Li polysulfides (LiPSs) and the sluggish transition of soluble LiPSs to insoluble Li 2 S or elemental S. Here, we report that Ni hexatomic clusters embedded in a nitrogen-doped three-dimensional (3D) graphene framework (Ni-N/G) possess stronger interaction with soluble polysulfides than that with insoluble polysulfides. The synthetic electrocatalyst deployed in the sulfur cathode plays a multifunctional role: (i) selectively adsorbing the polysulfides dissolved in the electrolyte, (ii) expediting the sluggish liquid-solid phase transformations at the active sites as electrocatalysts, and (iii) accelerating the kinetics of the electrochemical reaction of multielectron sulfur, thereby inhibiting the dissolution of LiPSs. The constructed S@Ni-N/G cathode delivers an areal capacity of 9.43 mAh cm -2 at 0.1 C at S loading of 6.8 mg cm -2 , and it exhibits a gravimetric capacity of 1104 mAh g -1 with a capacity fading rate of 0.045% per cycle over 50 cycles at 0.2 C at S loading of 2.0 mg cm -2 . This work opens a rational approach to achieve the selective adsorption and expediting of polysulfide transition for the performance enhancement of Li-S batteries.

The development of sodium-ion batteries (SIBs) is hindered by the rapid reduction in reversible capacity of carbon-based anode materials. Outside-in doping of carbon-based anodes has been extensively explored. Nickel and NiS2 particles embedded in nitrogen and sulfur codoped porous graphene can significantly improve the electrochemical performance. Herein a built-in heteroatom "self-doping" of albumen-derived graphene for sodium storage is reported. The built-in sulfur and nitrogen in albumen act as the doping source during the carbonization of proteins. The sulfur-rich proteins in albumen can also guide the doping and nucleation of nickel sulfide nanoparticles. Additionally, the porous architecture of the carbonized proteins is achieved through removable KCl/NaCl salts (medium) under high-temperature melting conditions. During the carbonization process, nitrogen can also reduce the carbonization temperature of thermally stable carbon materials. In this work, the NS-graphene delivered a specific capacity of 108.3 mAh g-1 after 800 cycles under a constant current density of 500 mA g-1 . In contrast, the Ni/NiS2 /NS-graphene maintained a specific capacity of 134.4 mAh g-1 ; thus the presence of Ni/NiS2 particles improved the electrochemical performance of the whole composite.

Bifunctional electrocatalysts for the oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) in alkaline electrolyte may improve the efficiency of overall water splitting. Nickel cobaltite (NiCo2 O4 ) has been considered a promising electrode material for the OER. However, NiCo2 O4 that can be used as an electrocatalyst in HER has not been studied yet. Herein, we report self-assembled hierarchical NiCo2 O4 hollow microcuboids for overall water splitting including both the HER and OER reactions. The NiCo2 O4 electrode shows excellent activity toward overall water splitting, with 10 mA cm(-2) water-splitting current reached by applying just 1.65 V and 20 mA cm(-2) by applying just 1.74 V across the two electrodes. The synthesis of NiCo2 O4 microflowers confirms the importance of structural features for high-performance overall water splitting.

A Hopfield neural network(HNN)identification approach is proposed for the hysteresis nonlinear system with Preisach model. Firstly, the Preisach model is applied and the designed HNN is transformed into matrix notation. Afterwards, two energy functions are proposed for the hysteresis system to estimate the unknown parameters. Finally, the detail of the identification is verified by constant and time-varying coefficients, and that the identification results are verified the effectiveness of the proposed approach.

Uniform nitrogen-doped C/Ni/TiO2 hollow spindles were successfully prepared with Ni nanoparticles encapsulated into the hollow N-doped TiO2/C matrix. This intriguing architecture not only exhibits favorable conductivity, but also provides a large quantity of accessible active sites for lithium ion insertion, thus contributing to superior lithium storage properties.

Ni–Co sulfides are considered as promising electrode materials for electrochemical pseudocapacitors because of their rich redox chemistry and great structural flexibility with low cost. However, traditional Ni–Co sulfides still suffer from poor electrochemical performance due to relatively low electronic conductivity and structural instability. Herein, we present facile syntheses of hollow Ni–Co sulfide nanoboxes with tunable compositions, i.e., NiCo2S4 and Ni2CoS4, by using a low-temperature wet-chemical method. The resultant Ni–Co sulfides demonstrate high specific capacitances with enhanced cycling stability and rate capability. The NiCo2S4 electrode exhibits a capacitance of 1588 F g−1 at 2 A g−1 and a capacitance retention of 88.2% at 5 A g−1 after 4000 cycles, while the Ni2CoS4 electrode exhibits a capacitance of 1200 F g−1 at 2 A g−1 and a capacitance retention of 90.5% at 5 A g−1 after 4000 cycles. All the experimental results illustrate nanostructured Ni–Co sulfides to be promising electrode materials for high-performance supercapacitors.

Han, C.; Zhang, X.; Li, L.; Chen, S.; Yan, Z.; Gao, X., and Chang, J., 2018. Analysis and evaluation of tetrodotoxin in coastal aquatic products of Zhejiang Province. In: Liu, Z.L. and Mi, C. (eds.), Advances in Sustainable Port and Ocean Engineering. Journal of Coastal Research, Special Issue No. 83, pp. 380–385. Coconut Creek (Florida), ISSN 0749-0208. A total of 306 coastal aquatic products were collected from representative aquaculture area and local markets in Zhoushan, Taizhou and Wenzhou cites of Zhejiang province between 2013 and 2014.Tetrodotoxin (TTX) content in edibletissue was analyzed by means of the ultrahigh performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS) in multiple reactions monitoring mode. In May, detection rate reached its peak in Zhoushan (8.33%) and Wenzhou (13.3%) cities, while a maximum detection rate of 33.3% in Taizhou city was found until June.Out of the captured and processed aquatic products, puffer fish (Lagocephalus gloveri), horseshoe crab (...

A method for the rapid determination of 4-hexylresorcinol (4-HR) residue in shrimp by solid phase extraction (SPE) ultra-high performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) was established. 4-HR was extracted twice with methanol, and the extract was formulated into methanol-water solution (1:1). After being cleaned up and concentrated by a PRIME HLB solid phase extraction column, the sample was analyzed by UPLC-MS/MS and quantitatively determined by an external standard method. The separation was performed with a gradient system consisting of water and acetonitrile as the mobile phase. Monitoring was performed by electrospray ionization (ESI) in negative ion mode using multiple ion reaction monitoring (MRM). Good linearity was obtained in the concentration range of 1.0&ndash, 100.0 &mu, g/L, with correlation coefficients larger than 0.999. The limit of detection (LOD) was 0.25 &mu, g/kg and the limit of quantification (LOQ) was 0.80 &mu, g/kg. The average recoveries of 4-HR at spiked concentrations of 2.40, 6.40 and 16 &mu, g/kg ranged from 81.35% to 94.68% with the relative standard deviations (n = 6) from 3.57% to 6.86%. The results showed that the method is simple, fast, sensitive, reliable, and reproducible, thus, it could be used as a rapid confirmation and quantitative analysis method of 4-HR residue in aquatic products.