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Metal sites (Ni, Bi or Ag) were introduced into carbon strengthened expanded graphite (CEG) based photocatalysts, and performed as a novel strategy to enhance the elimination of Microcystis aeruginosa and microcystin-LR from water. Results show that metal doping can efficiently improve the adsorption of harmful algae and enhance the photocatalytic activities in inactivation of harmful algae and degradation of MC-LR. Among the CEG catalysts, Ni-CEG can achieve the highest removal rate up to 90.6% for algal cells with 5 h visible light irradiation, while Bi-CEG catalyst provides the best performance for MC-LR degradation with the removal rate of 80.9% in 6 h visible light irradiation. In general, considering the coexistence of algal cells and microcystin-LR, Bi-CEG is proved to be an excellent candidate for the remediation of eutrophicated waters since it can achieve the efficient removal of both harmful algae and MC-LR. DFT calculations indicate that metal doping can transform the photocatalysts into n-type semiconductor, and provide the mid-gap state. In addition, the partial charge density distribution near Fermi level was mainly composed by the metal dopants, which can enhance the interaction with harmful algae and MC-LR.

Constructing Z-scheme heterojunction photocatalyst with strong redox ability to make for enhanced photocatalytic performance and efficient charge separation is extremely attractive but still underdeveloped. Herein, a Z-scheme heterojunction structured La(OH)3@In2S3 composite (labeled by “LIS”) with photocatalytic for the methylene orange (MO) degradation under simulated light irradiation has been developed. The as-prepared LIS, together with commercial La(OH)3 and pure In2S3 fabricated with the identical processing method and starting materials as those of LIS, was characterized by X-ray diffraction, UV–vis diffuse reflectance spectra, scanning electron microscopy, high-resolution transmission electron microscopy, X-ray photoelectron spectroscopy, photoluminescence spectra and electrochemical impedance spectroscopy. The results show the heterojunction of La(OH)3/In2S3 has prolonged the lifetime of the photo-generated carriers. The photocatalytic activity test shows that over only a small amount (0.02 g in 100 ml MO) of LIS, the photodegradation rate of 95% toward MO can be obtained in 90 min, which is about 3.4 times higher than that over pure In2S3. The active species trapping experiments indicate that there were four active species playing roles in photodegradation as the following order: e– = ∙OH

Typical desalination techniques, such as reverse osmosis, distillation, capacitive deionization, and battery desalination, require lots of electrical or thermal energy consumption. As a new emerging desalination technique, the solar-driven photoelectrochemical desalination (SD-PED) technology by using sustainable solar energy to remove salt ions without any external bias has been developed and caused much attention. The SD-PED technique with dual functions of desalination and photoelectric conversion driven by sunlight has demonstrated that a high initial photocurrent up to 9.5 mA can be obtained in the existing work with 99.95% salt removal rate. However, some limitations are remained such as the fast decline of photocurrent, difficulty in the seawater desalination, the long-term stability of system etc. To better understand this new desalination technique, herein, we comprehensively review and discuss the status of SD-PED system for the first time, including the device configuration, influencing factors and the active involved materials of solar absorbers and redox electrolyte species. Further, the strategies to improve the performance of long-term stability desalination are summarized, such as the configuration connection in series or parallel, the combination of photoanode and photocathode, the photosensitive material with wide solar absorption. At last, the challenge and prospect are further guided for the future development of SD-PED technology, which are expected to realize the commercialization.

Rechargeable aqueous zinc-ion batteries (ZIBs) are promising candidates in energy storage because of intrinsic safety, low-cost and eco-friendliness. However, restricted by cathode materials, ZIBs usually exhibit inferior capacity and limited cycling performance. Herein, an efficient dual-phase strategy is employed to fabricate novel heterogeneous K0.5V2O5 /NaV3O8 (KNaVO) hybrid cathode. In traditional aqueous batteries, the hybrid persistently offers long lifespan zinc-ions storage with reversible capacity of 150 mAh g−1 up to 5500 at 5 A g−1, and impressive rate performance with 128.7 mAh g−1 even at 10 A g−1 due to the ameliorated conductivity and conspicuous pseudocapacitance effect. In quasi-solid-state batteries, the flexible ZIBs can well withstand large-angle deformation from 30° to 120°. And at a large bend angle, ZIBs harvest the considerable capacity of 138.4 mAh g−1 after 1050 cycles at 1 A g−1 due to robust mechanical strength of gel electrolyte and enhanced Zn-storage of dual-phase structured KNaVO. This will be a prospect of applying flexible quasi-solid-state ZIBs in portable and wearable electronics.

In this study, we reported the biological approach to synthesis of ZnO nanorod (NR) on the reduced graphene oxide (RGO) for photocatalytic, antibacterial activity and hydrogen production under sunlight. Bacillus subtilis played a vital role in the production of biogenic ammonia from synthetic urine and utilized for the synthesis of ZnONR on the RGO sheet. The morphological study revealed that RGO sheets displayed a tremendous role in anchoring ZnONR. XRD patterns showed the ZnO crystal phase on the RGO sheets. XPS and Raman spectra confirmed that the bio-hydrothermal method as suitable for GO converted into RGO. The transient photocurrent and I/V measurement are exhibited as an increment on the RGO-ZnONR compared to ZnONR. The RGO-ZnONR composites showed excellent performance with decolorization of MB and textile dyes and efficient control of the E. coli and S. aureus. RGO-ZnONR exhibited remarkable noted as a higher photocatalytic hydrogen evolution rate (940 μmol/h/gcat) than the ZnONR (369.5 μmol/h/g cat). As a result of photocatalytic performance to correlate with sunlight intensity was extensively studied. RGO plays an essential role in interface electron transfer from sunlight to ZnONR for enhancing •OH radical formation to cleavage of dye color substance and eradicated bacterial cells.

Desalination techniques, such as reverse osmosis, distillation, capacitive deionization, and battery desalination, require lots of electrical or thermal energy consumption. Herein, we propose a consumption-free electrochemical desalination method based on a light-driven photocathode with a Pt/CdS/Cu2ZnSnS4(CZTS)/Mo architecture. Modification of a CdS layer on CZTS can improve the desalination performance due to the formation of inner p–n junction between CdS and CZTS which enhances the separation of the photoexcited carriers without recombination. This photocathode-assisted electrodialysis desalination plays the dual functions of both energy conversion and ion removal with the blocking of ion exchange membranes. The [Fe(CN)6]3−/4− redox couples are recirculated between the anode and photo-cathode as the electrolyte while the salt streams are fed into the middle compartment. Under light illumination, this architecture produces photo-generated electrons to the redox couples with the conversion of [Fe(CN)6]3− to [Fe(CN)6]4− at the positive chamber, causing cation capture in the presence of an ion-exchange membrane. At the same time, [Fe(CN)6]4− is oxidized at the negative reservoir. The light-driven electrochemical reaction of electrolyte redox couples can result in a continuous desalination process. This work will be significant for consumption-free photoelectrochemical desalination research.

An aqueous chloride ion battery (CIB) is an emerging technology for electrochemical energy storage as well as battery desalination systems. However, the instability and decomposition of electrode materials in an aqueous medium is a major issue in CIBs. Herein, in one step, we synthesized fine antimony nanoparticles with a size of ∼20 nm on reduced graphene oxide (Sb@rGO) sheets using a hydrothermal route with facile and cost-effective processes. It is proposed as a new anode material and coupled with the AgCl cathode in an aqueous CIB. The specific capacity is maintained constantly at 51.6 mA h g-1 at a current density of 400 mA g-1 even after 200 cycles. In addition, characterization methods such as electrochemical analysis, X-ray diffraction, etc. were used to confirm the reaction mechanism. The chloride ion capture material developed in this research work will be significant for CIBs as an energy storage technology or battery desalination system.

Efficiently storing electricity generated from renewable resources and desalinating brackish water are both critical for realizing a sustainable society. Previously reported desalination batteries need to work in alternate desalination/salination modes and also require external energy inputs during desalination. Here, we demonstrate a novel zinc-air battery-based desalination device (ZABD), which can desalinate brackish water and supply energy simultaneously. The ZABD consists of a zinc anode with a flowing ZnCl

Encapsulating silicon (Si) nanoparticles with graphene nanosheets in a microspherical structure is proposed to increase electrical conductivity and solve stability issues when using Si as an anode material in lithium-ion batteries (LIBs). Currently the main strategies to produce high-quality Si-graphene (Si@Gra) electrodes are (1) chemical vapor deposition (CVD) of graphene grown in situ on Si by hydrocarbon precursors and (2) encapsulating Si with a graphene oxide followed by postannealing. However, both methods require a high-temperature and are costly and time-consuming procedures, which hinders their mass scalability and practical utilization. Herein, we report a Si@Gra composite with a ball-like structure that is assembled by a facile spray drying process without a postannealing treatment. The graphene sheets are synthesized by an electrochemical exfoliation method from natural graphite. The resulting Si@Gra composite exhibits a unique core-shell structure, from which the ball-like morphology and the number of graphene layers in the Si@Gra composites are found to affect both the electric conductivity and ionic conductivity. The Si@Gra composites are found to increase the capacity of the anode and provide excellent cycling stability, which is attributed to the high electrical conductivity and mechanical flexibility of the layered graphene; additionally, a void space in the core-shelled ball structure inside the Si@Gra compensates for the Si volume expansion. As a result, the Si@few-layer graphene ball anode exhibits a high initial discharge capacity of 2882.3 mA h g-1 and a high initial coulombic efficiency of 86.9% at 0.2 A g-1. The combination of few-layer graphene sheets and the spray drying process can effectively be applied for large-scale production of core-shell structured Si@Gra composites as promising anode materials for use in high-performance LIBs.

The emerging metal-halide perovskites are promising for next generation optoelectronic devices. Recently, all-inorganic halide perovskites have been developed and show significantly improved stability compared with organic-inorganic hybrid halide perovskites. Here, we report a facile method based on the coffee ring effect of solvents to synthesize dual-phase CsPbBr

Continuous and low‐energy desalination technologies are in high demand to enable sustainable water remediation. Our work introduces a continuous desalination process based on the redox reaction of a dual‐zinc electrode. The system consists of two zinc foils as redox electrodes with flowing ZnCl2 electrolyte, concentrated and diluted salt streams with three anion‐ and cation‐exchange membranes (AEM and CEM) separated configuration (AEM|CEM|AEM). If a constant current is applied, the negative zinc electrode is oxidized, and electrons are released to the external circuit, whereas the positive zinc electrode is reduced, causing salt removal in the dilution stream. The results showed that brackish water can be directly desalted to 380.6 ppm during a continuous batch‐mode process. The energy consumption can be as low as 35.30 kJ mol−1 at a current density of 0.25 mA cm−2, which is comparable to reverse osmosis. In addition, the dual‐zinc electrode electrochemical desalination demonstrates excellent rate performance, reversibility, and batch cyclability through electrode exchange regeneration. Our research provides a route for continuous low‐energy desalination based on metal redox mediators., Continuous desalination! A novel dual‐zinc electrode electrochemical desalination process allows continuous desalination at low energy consumption. Brackish water is directly desalted from 2000 to 380.6 ppm during a continuous batch‐mode process. The energy consumption is as low as 35.30 kJ mol−1 at a current density of 0.25 mA cm−2, which is comparable to reverse osmosis.

Herein, we propose a stable and efficient photo-driven electrochemical desalination technique without any external bias. The whole desalination process is driven by CdS quantum dots (QDs) sensitized BiVO4 photoanode, where I-/I3- redox couples are recirculated as the electrolyte. Two salt streams are sandwiched between the photoanode and cathode. The salt ions in desalted stream are continuously extracted by the redox reaction of I-/I3- electrolyte at their respective electrode chambers. The initial photocurrent of 2.58 mA/cm2 can be obtained in the present photoanode-assisted desalination device, which is much greater than the previous reported results. Besides, the electrical current of the photo-electricity conversion system is extremely stable in the current system. Within the four batch cycles, the variation of salt removal rate is as low as 2.3 μg/(cm2•min) without significant decay. The photoanode-electrolyte interface, charge separation and transportation are further investigated by photoluminescence, electrochemical impedance spectroscopy and Mott-Schottky analysis. The promising desalination performance can be attributed to the synergistic effect of CdS QDs and BiVO4 heterojunction which is applied in the field of solar-driven desalination for the first time. This work is significant for the design of high light-absorbing heterojunction photocatalysts for the dual functions of energy production and water desalination.

Flow-electrode capacitive deionization (FCDI) has developed as a promising technology to realize the highly efficient and low-energy-consumed desalination process. To deliver better desalination performance, the flow-electrode with high capacitance and low resistance is essential. As for the traditional AC flow-electrode, although it is low-cost and wide-applied, the relatively low capacitance and poor conductivity are the limitations for its further development. Here, we propose a novel flow-electrode material, nanoporous carbon polyhedron (NCP), which was prepared by ZIF-8 followed by carbonization and activation process and have a higher surface area and larger specific capacitance than AC. The desalination experiments showed that the current density of FCDI system based on NCP is about 2.5 times larger than that of AC, exhibiting a higher desalination rate of 20.98 μg cm−2 min−1 for NCP. Moreover, the desalination energy consumption and efficiency can keep relatively stable after the long-time continuous desalination cycling. This current research may be significant for the future promising application of high-performance FCDI system.

In redox flow electrode capacitive deionization (FCDI), the solubility of the redox electrolyte and flowability of the carbon slurry have a great influence on the salt removal rate and energy consumption. In this work, a mixed solvent electrolyte is proposed for FCDI, which consists of iodide/triiodide redox couples and a carbon slurry in a mixed solvent of water and ethanol (1:1). At a current density of 5 mA cm−2, the salt removal rate in the mixed solvent can reach up to 2.72 μg cm−2 s−1, which is much higher than the value of 1.74 μg cm−2 s−1 and 2.37 μg cm−2 s−1 obtained in aqueous and ethanol solutions, respectively. This is attributed to the fast transport of ions during the redox reaction in organic solvents and the excellent flowability of the carbon slurry under aqueous conditions, which can provide more reaction sites for iodide/triiodide redox reactions and faster electron transportation. This unique FCDI with organic and aqueous mixed solvent electrolytes provides a new perspective for the development of redox flow electrochemical desalination.

A novel Cr–Zn redox battery, which consists of K2Cr2O7 acid solution as cathode and metal zinc as anode, has been introduced to degrade Cr(VI) pollution and obtain electric energy. During the redox...

Lithium-sulfur battery has been considered to be one of the promising alternatives to the traditional lithium-ion battery due to its high theoretical energy density and saving-cost. However, the sluggish reaction during the decomposition of lithium sulfide results in a low specific capacity and poor cycling stability. Herein Co3O4 nano-particle embedded mesoporous carbon rod (Co3O4@MCR) was prepared through a template method to accommodate sulfur as cathode of lithium-sulfur battery. The resultant composite was characterized by Raman spectra, XRD, TEM, SEM, etc. The electrochemical investigation demonstrated that Co3O4@MCR composite exhibits enhanced electrocatalytic performance in lithium-sulfur battery, which was confirmed by cyclic voltammograms, galvanostatic charge-discharge testing, and study of sulfide oxidation using linear sweep voltammetry. With the current density of 0.2 A/g, the specific discharge capacity can be achieved up to more than 1000 mAh/g after 100 cycles. The enhanced electrocatalytic conversion from Co3O4@MCR leads to a low over-potential, fast lithium-ion kinetics and sulfide oxidation reaction.

In this work, it is successfully achieved to synthesize the three-dimensional flowerlike Ni(1-x)MnxFe2O4 (x = 0, 0.02, 0.04, 0.06, 0.08, 0.1) by an environmental hydrothermal method. The morphology and structure of as-prepared Ni(1-x)MnxFe2O4 are characterized via X-ray diffraction, scanning electronic microscopy and nitrogen adsorption-desorption isotherms, besides, the magnetic properties of the samples is revealed by vibrating sample magnetometer. The results show that the Ni(1-x)MnxFe2O4 are cubic spinel phase with three-dimensional flowerlike microspheres structure assembled by nanosheets, which is exhibited the good performance to remove Congo red (CR). Besides, the samples with good magnetic properties facilitates magnetic separation for CR solution. The kinetics and isotherm of adsorption process are studied via a UV–visible spectrophotometer. The adsorption process is found to fit the pseudo-second-order kinetic model and Freundlich isotherm model better. Moreover, the adsorption capability of CR on Ni(1-x)MnxFe2O4 has a great enhancement by the appropriate doping of Mn2+ ions. In order to research the mechanism of the CR adsorption process, the effect of pH value and the surface group of the samples and CR are measured. Due to the doping of Mn2+ ions, the surface activity of Ni(1-x)MnxFe2O4 has been changed and the adsorption capability (231.74546 mg g−1) of CR on Ni0.98Mn0.02Fe2O4 is maximum in the all samples at pH 5. This research suggests that appropriate doping of Mn2+ ions could enhance the adsorption performance for CR, which provides a new idea for the development of adsorbent.

Sulphur-containing chitosan, a water-soluble derivative of chitosan, was synthesized by using chitosan and other reagents. This sulphur-containing chitosan was combined with chitosan to recover ultra-trace palladium in HCl medium. The effects of the chelating dosages, pH, chelating precipitation rate, initial Pd concentration and coexisting cations were systematically investigated via chelating precipitation experiments. Under the optimized conditions, greater than 95% of palladium was recovered from the HCl medium, with pH ranging from 2 to 5.5 and proper dosages of chitosan and sulphur-containing chitosan, which were related to the concentration of Pd(II) ions. In addition, the presence of coexisting cations (Cu2+, Ni2+, Fe2+, and Sn2+) had no effect on the recovery rate of palladium. The recovery mechanism of palladium by chitosan and sulphur-containing chitosan was studied via molecular weight analyses, elemental analyses, FT-IR analyses and XPS analyses. The proposed chelating precipitation method was successfully applied to the recovery of ultra-trace palladium in HCl medium.

Layered Li-rich cathode materials Li1.2Mn0.534Ni0.133Co0.133O2 (LNCMN-0) and Na doping Li1.1Na0.1Mn0.534Ni0.133Co0.133O2 (LNCMN-0.1) are prepared successfully by a co-precipitation method and several consecutive calcination treatments. Besides, the phase structure, morphology, and electrochemical properties of the four samples are studied in detail using X-ray diffraction (XRD), scanning electron microscope (SEM), galvanostatic charge-discharge test, cyclic voltammetry (CV), and electrochemical impedance spectroscopy (EIS). Although the discharge capacity of spherical LNCMN-0.1 decreases slightly at 0.1 C (1 C = 250 mA g−1), compared to the pristine LNCMN-0, it is noteworthy that the LNCMN-0.1 matched with dual Li+/Na+ electrolyte exhibit superior stability performance at 1 C, as well as enhanced rate capability. The LNCMN-0.1 (Li+/Na+) delivers an initial discharge specific capacity of 267.61 mAh g−1 at 0.1 C between 2.0 and 4.8 V at room temperature and initial coulombic efficiency of 83.51%, which is higher than the LNCMN-0 samples (76.42 and 81.54%). The experimental results verify that Na doping combined with dual Li+/Na+ electrolyte can generate a synergistic effect, which is a promising idea to ameliorate the electrochemical performance for this material.

To reduce the influence from volume expansion of silicon during lithium lithiation/delithiation, milled flake graphite/plasma nano-silicon@carbon (MFG/PNSi@C) composite with void sandwich structure is synthesized by assembling thin MFG (thickness of 150 nm) sheets loading with carbon-coated PNSi (plasma nano-silicon) via a facile spray drying method. The MFG/PNSi@C composite, as lithium ion battery anode, exhibits excellent electrochemical performance at room temperature and displays an outstanding cyclic property even at high temperature. The MFG/PNSi@C electrode delivers reversible capacity of 1141 mAh g−1, and high initial Coulombic efficiency of 84.4%, and capacity retention of 84.1% after 200 cycles at a current density of 0.1 A g−1. Even at the current density of 0.2 and 0.4 A g−1, the reversible capacities of 1168 and 1102 mAh g−1 can be achieved respectively, with the capacity retention of 68.9% and 63.9% after 200 cycles. Even the work temperature goes up 60 °C, the discharge/charge capacities of 832/808 mAh g−1 can be obtained at a current density of 0.1 A g−1. The stable cyclic performance is mainly due to the void sandwich structure of the MFG/PNSi@C composite, which dramatically shortens lithium ion diffusion path and pitch carbon shell can buffer huge volume expansion.

Desalination battery, consisting of sodium and chloride dual-ion electrochemical electrodes, is an aqueous energy storage device for the use of seawater deionization. Herein, a novel and stable rechargeable desalination cell is demonstrated based on such dual-ion electrochemical deionization technology, comprising of NaTi2(PO4)3 anode and silver cathode in an aqueous NaCl electrolyte. During the charging process, sodium ions in electrolyte are electrochemically captured into NaTi2(PO4)3 electrode while chloride ions are captured and reacted with silver electrode to form AgCl, whereas discharging causes the release of sodium and chloride ions from the corresponding electrodes. The distinct charge/discharge plateaus are located at 0.86 V/0.76 V. The stable capacity of 37.4 mAh/g is achieved for 200 cycles at a current density of 1000 mA/g, and the corresponding energy efficiency is up to 71.9%. The calculated energy consumption of 3.80 Wh/L is obtained with the energy recovery during discharge process for converting seawater to fresh water. We believe it will contribute greatly towards future energy saving seawater desalination technologies.

A rod-like hollow graphitic carbon shell with nitrogen doping was fabricated via a template-assisted growth for enhanced capacitive deionization. The silica nanorods prepared as the templates have uniform structures, which can effectively avoid aggregation. Nitrogen-doped graphitic carbon is favourable for higher electrical conductivity. The hollow structure obtained after etching provides a large ion-accessible surface area. The resultant rod-like nitrogen-doped carbon hollow shells have a hierarchically porous architecture with high electrical conductivity and a beneficial porosity. In this work, the morphology, structure, specific surface area, and porosity were carefully investigated using SEM, TEM, XRD, Raman, BET and BJH methods. Electrochemical test and electrosorptive test were conducted to analyse the specific capacitance, electrosorption capacitance and cycle ability. The largest electrosorption capacity was achieved as 16.72 mg g−1 at 1.6 V in 250 mg g−1 solution. Moreover, the adsorption kinetics were investigated using Lagergeren’s model. Overall, the nitrogen-doped carbon hollow shell is demonstrated as a promising candidate of electrode material for water desalination via capacitive deionization.

Both freshwater shortage and energy crisis are global issues. Herein, we present a double-function system of faradaic desalination and a redox flow battery consisting of VCl3|NaI redox flow electrodes and a feed stream. The system has a nominal cell potential (E0 = +0.79 V). During the discharge process, the salt ions in the feed are extracted by the redox reaction of the flow electrodes, which is indicated by salt removal. Stable and reversible salt removal capacity and electricity can be achieved up to 30 cycles. The energy consumption is as low as 10.27 kJ mol-1 salt. The energy efficiency is as high as 50% in the current aqueous redox flow battery. With energy recovery, the desalination energy consumption decreases greatly to 5.38 kJ mol-1; this is the lowest reported value to date. This "redox flow battery desalination generator" can be operated in a voltage range of 0.3-1.1 V. Our research provides a novel method for obtaining energy-saving desalination and redox flow batteries.

Sodium ion batteries (SIBs) are proposed as alternatives to the current widely used lithium ion batteries (LIBs) due to the abundance of battery-grade sodium sources in nature. However, the search for suitable high-performance electrode materials for SIBs continues to remain a significant challenge. Herein, we report a hybrid nanoarchitecture with nitrogen-doped graphene quantum dots (NGQDs)-decorated WS2 nanosheets anchored on a porous three-dimensional carbon foam (NGQDs-WS2/3DCF) scaffold as the anode that enables long-term cycling and high rate capability for SIBs. Benefiting from the 3D robust porous interpenetrating framework and the NGQDs decoration, the NGQDs-WS2/3DCF nanoarchitecture exhibits a high rate capability with a capacity of 268.4 mA h g−1 at 2000 mA g−1, and a long lifetime with an extraordinary capacity retention of 97.1% over 1000 cycles. Furthermore, the pseudocapacitance contributions of the NGQDs-WS2/3DCF nanoarchitecture are quantified by an in-depth kinetics analysis, which provides a better understanding of the excellent electrochemical performances. Remarkably, a cable-shaped flexible full SIB was also demonstrated using NGQDs-WS2/3DCF as the anode electrode, which exhibits high capacity and excellent flexibility. The nanoarchitecture fabrication approach and the surface engineering strategy as well as the demonstrated cable-shaped configuration may open an avenue for the development of wearable SIBs with high performance.

The articulate combination of intriguing functional groups and luminescence properties can deliver metal-organic frameworks (MOFs) with multifarious applications viz. selective and specific sensing of nitroaromatic compounds (NACs), an important constituent of explosives, as well as sensing of toxic metal ions. In this regard, a new d10 configuration based Zn(ii) metal-organic framework (MOF) {(NH2(CH3)2)[Zn4(ddn)2(COO)(H2O)4]·solvent}n (1) has been synthesized using a π-conjugated and rigid multicarboxylate ligand 3,5-di(3,5-dicarboxylphenyl)nitrobenzene (H4ddn). 1 displays a 3D (3,4,6)-c connected net which is based on two types of binuclear [Zn2(μ2-COO)2(μ1-COO)2] and [Zn2(μ2-COO)4] clusters. Sensing studies of 1 to detect nitro-aromatic compounds reveal highly specific detection of 2,4-dinitophenol (DNP) with remarkable quenching (KSV = 8.93 × 103 M-1) and a low limit of detection (LOD: 1.12 ppm). The luminescence quenching mechanism in the case of 1 in the presence of NACs has been ascribed to the concurrent presence of the charge transfer as well as the weak interaction between the MOF and NACs. The activated framework of 1 also displayed highly selective detection of ferric ions with KSV = 1.13 × 104 M-1 with a low limit of detection (LOD: 1.24 ppm).

The anion battery system is a new research area in the energy storage field. Herein, a novel aqueous rechargeable dual-ion battery based on fluorine ion and sodium ion electrochemistry is proposed, consisting of bismuth fluoride as the anode, sodium manganese oxides (NMO) as the cathode and aqueous NaF solution as the electrolyte. The bismuth fluoride electrode can electrochemically release/capture fluoride ion in aqueous electrolyte and sodium ion can be de-intercalated/intercalated at the NMO cathode during charge/discharge process. The electrochemical behavior was confirmed by cyclic voltammetry, charge–discharge curves as well as X-ray powder diffraction. The reversible and stable discharge capacity is obtained with a coulombic efficiency of 98.44%. After 40 cycles, the specific capacity can be still maintained at 47.28 mAh g−1 at the current density of 100 mA g−1. The current battery system possesses excellent rate performance. It can operate at 3200 mA g−1 (10.6C) with 82.8% specific capacity as that at 100 mA g−1. This is the first demonstration that the aqueous dual-ion battery can work based on fluoride ion and sodium ion electrochemistry and it will be significant for future energy storage and ion removal.

As anodes for metal-ion batteries, metal phosphides usually suffer from severe capacity degradation because of their huge volume expansion and unstable solid electrolyte interphase (SEI), especially for potassium-ion batteries (PIBs). To address these issues, this study proposes amorphous phosphates acting as buffer materials. Ten types of metal phosphide composites embedded with in situ-formed amorphous phosphates are prepared by one-step ball milling using red phosphorus (RP) and the corresponding metal oxides (MOs) as starting materials. A zinc phosphide composite is selected for further study as a PIB anode. Benefitting from the effective suppression of volume variation, a KF-rich SEI is formed on the electrode surface in the KFSI-based electrolyte. The zinc phosphide composite exhibits a high reversible specific capacity and outstanding long-term cycling stability (476 mAh g −1 over 350 cycles at 0.1 A g −1 after going through a rate capability test and 177 mAh g −1 after 6000 cycles at 1.0 A g −1) and thus achieves the best cycling performance among all reported metal phosphide-based anodes for PIBs. This study highlights a low-cost and effective strategy to guide the development of metal phosphides as high-performance anodes for PIBs.

The ever-increasing demand for powering wearable electronics, energy concern, and climate crisis, arouse attention for developing energy storage systems with high energy and power density, long cycling life, and excellent mechanical flexibility. Herein, we demonstrate a hierarchical 3D electrode for high-performance flexible supercapacitors, in which metallic molybdenum disulfide (MoS2) nanosheets are uniformly deposited on the surface of carbon nanocones (CNC) grown on carbon cloths (CC), yielding CC-CNC@MoS2. The 3D CC-CNC substrate provides a large surface for high mass loading of MoS2, a high pathway for fast electron transfers as well as the porous structure for efficient electrolyte ion diffusion to access active materials. Also, the layered structure of metallic MoS2 nanosheets enables large amounts of active sites and facilitates ion transport as well. Benefitting from the rational nanostructure design, the assembled quasi-solid-state supercapacitor yielded a maximum energy density of 0.016 mWh cm−2 and a peak power density of 8.3 mW cm−2, and ultra-high cycling stability over 10,000 cycles, outperforming many recently reported flexible supercapacitors. Furthermore, the excellent mechanical properties of both CC-CNC substrates and MoS2 nanosheets endow the resulting quasi-solid-state supercapacitors with compelling flexibility for wearable electronics. Finally, an energy storage unit fabricated from the supercapacitors could light an LED, demonstrating its great application potential in wearable electronics.

Solar-assisted electrochemical desalination has offered a new energy-water nexus technology for sustainable development in recent studies. However, only a few reports have demonstrated insufficient photocurrent, a low salt removal rate, and poor stability. In this study, a high-quality freshwater level of 5-10 ppm (from an initial feed of 10 000 ppm), an enhanced salt removal rate (217.8 µg cm-2 min-1 of NaCl), and improved cycling and long-term stability are achieved by integrating dye-sensitized solar cells (DSSCs) and redox-flow desalination (RFD) under light irradiation without additional electrical energy consumption. The DSSC redox electrolyte (I- /I3- ) is circulated between the photoanode (N719/TiO2 ) and intermediate electrode (graphite paper). Two DSSCs in parallel or series connections are directly coupled to the RFD device. Overall, this hybrid system can be used to boost photo electrochemical desalination technology. The energy-water nexus technology will open a new route for dual-role devices with photodesalination functions without energy consumption and solar-to-electricity generation.

Prussian blue analogues (PBAs) have emerged as efficient catalysts for oxygen evolution reaction (OER) due to their porous structure with well-dispersed active sites. However, Co-based PBA (Co-PBA) electrocatalysts are characterized by moderate OER kinetics. In this study, we developed a facile high-yield strategy to fabricate defective Co-PBA (D-Co-PBA) with [Fe(CN)6] vacancies and exposed Co (III) active sites by post-oxidation treatment of the pristine Co-PBA with aqueous H2O2 . Rietveld refinement results show that the lattice parameter (a) and unit-cell volume (V) of D-Co-PBA are smaller than those of the pristine Co-PBA, thereby confirming the generation of [Fe(CN) 6] vacancies. Density functional theory calculations reveal that the [Fe(CN)6] vacancy can effectively regulate the electronic structure of D-Co-PBA; this condition reduces the reaction barrier of the rate-determining step toward OER. In OER, the D-Co-PBA catalyst achieves a lower overpotential of 400 mV at a current density of 10 mA cm−2, which is superior to that of Ir/C (430 mV) and Co-PBA (450 mV). A hybrid sodium–air battery assembled with Pt/C and D-Co-PBA catalysts displays a discharge voltage of 2.75 V, an ultralow charging–discharging gap of 0.15 V, and a round-trip efficiency of 94.83% on the 1000th cycle at the current density of 0.01 mA cm−2. This study is highly promising for large-scale production of affordable and effective PBA-based materials with desirable OER activity for metal-air batteries and water-alkali electrolyzers, thus helping achieve the goal of sustainability.

In recent years, the increasing demand for energy has spurred the development of novel and effective energy storage technologies which are safe and reliable. Herein, we introduce an aqueous rechargeable battery comprising of a bismuth oxychloride (BiOCl) anode and a silver cathode in an aqueous NaCl electrolyte solution. This innovative way of energy storage is based on a redox reaction involving the shuttling of chloride ions between the two electrodes. During the charging process, chloride ions are released from the anode and intercalated into the cathode whereas discharging causes the extraction of chloride ions from the cathode and the recovery of BiOCl at anode side. This new battery system can deliver a stable and reversible capacity of 92.1 mAh g−1 when operated at a current density 400 mA g−1. Further investigations involving the reaction mechanisms are given by X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDS). This aqueous chloride ion battery is the first of its kind and we believe it will contribute greatly towards future battery technologies.

Seawater desalination is a leading method for tackling the challenge of global freshwater shortage. However, existing desalination technologies like capacitive deionization (CDI) have their own limits, including high energy consumption or low ion removal capacity, which is not sufficient for desalting high-concentration saline water with low cost. Herein, we present a concept of flow dual-ions electrochemical deionization technology, which consists of BiOCl for chloride ion Faradaic electrode on the negative side, sodium manganese oxide (Na0.44MnO2) as sodium ion Faradaic electrode on the positive side, and a flow salt feed as electrolyte. It utilizes a redox reaction to individually capture chloride ions and sodium ions concurrently. Under positive electric current operations, the two ions are released for NaCl water electrolyte to flow. On switching to negative electric current, the chloride ions are extracted into the negative electrode, and thus prevented from flowing into the NaCl solution while sodium ions are electrochemically captured into the positive electrode. The novel dual-ions in Faradaic deionization deliver a stable and reversible salt removal/release capacity of 68.5 mg g−1 when operated at a current density 100 mA g−1, which indicates an amount over twice the salt absorption amount of the previously reported best performance (31.2 mg g−1) obtained by a hybrid capacitive deionization system. The electric charge efficiency is up to 0.977 during salt desorption process and 0.958 during absorption process. Owing to the salt removal, energy will be released during discharge process; therefore, the current system is called “desalination generator”. Our research will supply a new method for desalination flow-through system.

Novel desalination technologies with high ion removal capacity and low energy consumption are desirable to tackle the water shortage challenge. Herein, we report a dual-ion electrochemistry deionization (DEDI) system with silver chloride as the electrochemical chloride release/capture anode, sodium manganese oxide as the electrochemical sodium release/capture cathode, and flow salt solution as the electrolyte. Sodium and chloride ions are synergistically released to the flow electrolyte feed at an applied positive current. Under negative current conditions, the two ions are extracted from the flow electrolyte feed to their corresponding electrodes at the same time, which can cause a conductivity decrease indicating salt removal. The salt absorption/desorption capacity of the novel deionization system is stable and reversible, up to 57.4 mg g−1 for 100 cycles, which is much higher than that obtained by conventional or hybrid capacitive deionization devices. The charge efficiency is 0.979/0.956 during the salt desorption/absorption process. This research will be of great significance for high efficiency and low energy consumption seawater desalination.

Capacitive deionization (CDI) has emerged as a simple, energy efficient, environment-friendly and cost effective technology for desalination of saline water in recent years. However, the salt removal capacity of CDI systems is not sufficient for desalting high-concentration seawater. Here we report a novel electrochemical deionization (EDI) system based on a NaTi2(PO4)3/rGO (NTP/rGO) composite, operated in a constant current mode. During the desalination process, sodium ions in the NaCl solution will be intercalated into the NTP/rGO electrode via a chemical reaction, while chloride ions are physically adsorbed on the other activated carbon (AC) electrode. The NTP/rGO based EDI system shows ultrahigh desalination performance. The salt removal capacity can reach 140 mg g−1 in the first cycle with a current density of 100 mA g−1, decreasing to as low as 120 mg g−1 after 100 cycles. Furthermore, a particularly rapid desalination rate of 0.45 mg g−1 s−1 has been achieved at 1000 mA g−1 with a removal capacity of 27 mg g−1. The excellent performance of the EDI system in this work has made it a promising desalination technology and provides great potential for direct seawater desalination in the future.

Highlights Divalent magnesium ions as electrolyte additives are first used to improve the performance of vanadium-based cathodes for aqueous ZIBs.Pre-adding magnesium ions into electrolytes provide an appropriate equilibrium balance between the dissolution and recombination of magnesium vanadates, thus suppress the continuous dissolution of active materials, and lead to a higher stability of the electrode.The hybrid aqueous electrolytes with cost-effective ZnSO4 and MgSO4 salts show a better competitive prospective for the stationary grid-scale applications. Electronic supplementary material The online version of this article (10.1007/s40820-020-0385-7) contains supplementary material, which is available to authorized users., MgSO4 is chosen as an additive to address the capacity fading issue in the rechargeable zinc-ion battery system of MgxV2O5·nH2O//ZnSO4//zinc. Electrolytes with different concentration ratios of ZnSO4 and MgSO4 are investigated. The batteries measured in the 1 M ZnSO4−1 M MgSO4 electrolyte outplay other competitors, which deliver a high specific capacity of 374 mAh g−1 at a current density of 100 mA g−1 and exhibit a competitive rate performance with the reversible capacity of 175 mAh g−1 at 5 A g−1. This study provides a promising route to improve the performance of vanadium-based cathodes for aqueous zinc-ion batteries with electrolyte optimization in cost-effective electrolytes. Electronic supplementary material The online version of this article (10.1007/s40820-020-0385-7) contains supplementary material, which is available to authorized users.

The lack of an effective and practical quality control method for industrialized bamboo bundle veneers is the key restriction in the application of bamboo bundle composite materials in the field of construction. In this work, the density uniformity and mechanical properties of bamboo bundle veneers were systematically evaluated by the combination of light transmittance and mechanical stiffness. It was found that the number of broomings, dippings, and high-temperature heat treatments had different effects on the bamboo bundle veneers. On this basis, the uniformity of the density and mechanical properties of the bamboo scrimber (BS) that underwent hybrid paving, and the bamboo bundle laminated veneer lumber (BLVL), were analyzed. The results showed that the performance stability of bamboo bundle composites could be greatly improved by bamboo bundle veneer laminated paving. A large-scale quality evaluation system for bamboo bundle veneers was established in this work, and it provides conditions for the manufacture of bamboo bundle composites with stable and controllable performance.

A ratiometric fluorescent sensor for the detection of Fe

Two-dimensional (2D) metal dichalcogenides have attracted considerable attention for use in photoelectric devices due to their unique layer structure and strong light-matter interaction. In this paper, vertically grown SnS2 nanosheets array film was synthesized by a facile chemical bath deposition (CBD). The effects of deposition time and annealing temperature on the quality of SnS2 films was investigated in detail. By optimizing the preparation conditions, the SnS2 array film exhibited efficient photoelectric detection performance under sunlight. Furthermore, in order to improve the performance of the photodetector based on SnS2 nanosheets film, a transparent graphene film was introduced as the hole-transport layer by wet-chemical method directly transferring techniques. Graphene/SnS2 nanosheets array film heterojunction photodetectors exhibit enhanced photoresponsivity. The light on/off ratio of the photodetector based on graphene/SnS2 was 1.53, about 1.4 times higher than that of the pristine SnS2 array films. The improved photoresponse performance suggested that the effective heterojunction between vertical SnS2 nanosheets array film and graphene suppresses the recombination of photogenerated carriers. The results indicate that the graphene/SnS2 heterojunction photodetectors have great potential in photodetection devices.

The objective of this study was to investigate the hygroscopic characteristics of three typical bamboo engineering composites (Bamboo scrimber (BS), bamboo bundle/wood laminated veneer lumber (BLVL), and bamboo laminated timber (BLT)) as well as predict their performance changes and service life in hot humid environments. The composites were subjected to three treatment conditions (23 &deg, C, 63 &deg, C, and 100 &deg, C) for this experiment. The hygroscopic thickness swelling model and Fick&rsquo, s second law were used to quantify the characterization and prediction of the water absorption, thickness swelling rate, and water absorption rate of BS, BLVL, and BLT. The results indicated that the order of the hygroscopic thickness swelling coefficient KSR and the diffusion coefficient D was BLT &gt, BLVL &gt, BS (at 23 &deg, C and 63 &deg, C). The optimal dimensional stability was displayed by BS, followed by BLVL and BLT. In addition to the hygroscopic properties, elastic modulus degradation was investigated. It was observed that the elastic modulus (MOR) degradation had a linear relationship with the aging temperature. After 152 h of the hydrothermal aging test (63 &deg, C), the MOE of BS, BLVL, and BLT degraded by 44.33%, 53.89%, and 25.83%, respectively.