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A gemini-type iridium(III) complex was designed, synthesized, and served as both a photoinitiator and a surfactant to polymerize styrene in aqueous solution. Under visible light irradiation, polystyrene with a uniform sphere morphology and ultra-bright luminescence was obtained. This new methodology provided a simple, eco-friendly and unique platform for the preparation of phosphorescent polymeric nanomaterials.

High-performance hydrogel electrolytes with eminent toughness, high conductivity and anti-freezing properties have extensive applications in wearable devices or implantable sensors. However, it is still difficult to integrate excellent mechanical properties and high conductivity into one hydrogel sample simultaneously. This work introduced NaCl into a poly(vinyl alcohol)/poly(acrylic amide) (PVA/PAM) double network hydrogel to prepare PVA/PAM/NaCl supramolecular hydrogel electrolytes via a one-pot method. NaCl introduces physical entanglement into the PVA/PAM/NaCl hydrogel electrolytes and provides a dense and wrinkled three dimensional (3D) network nanostructure. The PVA/PAM/NaCl hydrogel electrolytes not only showed excellent mechanical properties (tensile strength up to 477 kPa, elongation at break to 1072% and a fracture energy of 2.484 MJ m−3), but also had high conductivity (up to 6.23 S m−1). A strain sensor based on the PVA/PAM/NaCl hydrogel electrolytes exhibited very high sensitivity (gauge factor = 24.901) with the ability of precise and reliable detection of human motions. Hydrogels also showed excellent anti-freezing properties and maintained excellent mechanical properties and conductivity at −20 °C. Introducing a physically cross-linking network through the effects of a metal salt could promote the performance of the hydrogels. This work provides a new insight into the design of multifunctional materials with applications on electronic skin, wearable devices and biosensors.

The rapid development of human–machine interface technologies is dependent on flexible and wearable soft devices such as sensors and energy storage systems. One of the key factors for these devices is the hydrogel electrolyte. In this work, firstly we constructed an anti-freezing, self-healing, adhesive and tough conductive double network ionic organohydrogel by simultaneously introducing NaCl and glycerol (Gly) into poly(vinyl alcohol)/poly(acrylic amide-acrylic acid) (PVA/PAMAA). Then, based on this organohydrogel, a strain sensor and a flexible all-solid-state supercapacitor were assembled separately and their properties were measured. The fabricated strain sensor showed a highly sensitive response (gauge factor = 8.303) in a broad strain range (from 500 to 1000%), enabling the accurate and reliable detection of various mechanical deformations. Meanwhile, the flexible all-solid-state supercapacitor demonstrated a specific capacitance of 75.75 mF cm−2, high cycling stability (90.2% retention rate after 5000 cycles) and excellent mechanical stability. Lastly, a self-powered integrated system composed of the strain sensor and flexible all-solid-state supercapacitor was fabricated. The sensor can be driven by the supercapacitor and operate stably in a wide strain range sensing test with low power consumption. More importantly, the self-powered integrated system could be directly attached to the human body to detect human motions, showing its great potential application in wearable devices. This work would enlarge the research and application of high-performance ionic hydrogel electrolytes.

Developing high active and earth-abundant electrocatalysts is a challenge for commercialization of dye-sensitized solar cells (DSSCs). Herein, a designed synthesis of CoTe2 nanoparticles embedded in nitrogen-doped carbon nanotubes-grafted polyhedron (CoTe2@NCNTs) using zeolitic imidazolate framework-67 (ZIF-67) as template is reported. Benefiting from the high surface area induced by the in situ growth of CNTs and the synergistic effect between CoTe2 and the N-doped nanostructured carbon, CoTe2@NCNTs hybrids exhibit remarkable catalytic activity toward the reduction of I3− ions. When employed as counter electrode (CE) of DSSCs, CoTe2@NCNTs hybrids deliver overwhelming power conversion efficiency (PCE) of 9.02%, possessing ~12% improvement compared with the Pt CE (8.03%). This study provides an emerging substitute for traditional Pt CE and a strategy to synthesize efficient electrocatalysts via rational surface engineering.

Clinical diagnostics and therapeutics of tumors are significantly benefitted by the development of multifunctional theranostic agents, which integrate tumor targeting, imaging, and therapeutics. However, the integration of imaging and therapy functionalities to a unimolecular framework remains a great challenge. Herein, a family of amphiphilic gemini iridium(III) complexes (GIC), Ir1-Ir6, are synthesized and characterized. The presence of quaternary ammonium (QA) groups endows GIC with adjustable water solubility and excellent self-assembly properties. Spectroscopic and computational results reveal that introducing QA groups into cyclometalating ligands (ĈN ligands) can overcome the drawback of aggregation-caused emission quenching and ensure Ir1-Ir3 with high emission intensity and excellent singlet oxygen (1O2) generation ability in aqueous media. Cell-based assays indicate that Ir3 shows higher cellular uptake efficiency and localizes specifically in the mitochondria, as well as exhibits outstanding photostability and an impressive phototoxicity index with satisfactory performance in mitochondria-targeted imaging and photodynamic therapy (PDT) of tumor cells. Furthermore, in vivo studies further prove that Ir3 possesses excellent antitumor activity and remarkably inhibits the growth of the HepG2 cells under PDT treatment. Consequently, this study presents a promising strategy for designing clinical application potential multifunctional iridium complex theranostic agents for mitochondria-targeted imaging and PDT in a single molecular framework.

In this work, a nitrogen-doped activated mesoporous carbon aerogel (NAMC) for the removal of methyl orange from aqueous solution was prepared through carbonization and pickling using the chitosan and poly(vinyl alcohol) as the carbon source and AlCl3·6H2O as both the solvent for chitosan and the hard template for porous structure. The morphology and structural properties were characterized by N2 adsorption–desorption isotherms, scanning electron microscopy (SEM), X-ray diffraction measurement, and Raman spectroscopy, respectively. The effects of pickling time and initial aqueous concentration on the adsorption were investigated. The SEM results showed that the pickling caused NAMC to have the porous structure and thus improved the adsorption of NAMC for MO. The adsorption kinetics was studied by the pseudo first-order, pseudo second-order and intra-particle diffusion rate models, respectively. This work provides a practical utilization route for chitosan.

In this work, a gemini-surfactant (i.e. sodium dilauramino cysteine, SDLC) stabilized high internal phase emulsion (HIPE) template was utilized to prepare monolithic polyHIPEs of chitosan-g-polyacrylamide (CT-g-PAAm) for the first time. The influences of internal phase fraction and emulsifier concentration on the porous structures were studied. The morphologies of polyHIPEs were observed via scanning electron microscope (SEM) while structure parameters were investigated by combining nitrogen adsorption/desorption measurements with mercury intrusion porosimetry (MIP). Highly porous polyHIPEs of CT-g-PAAm with porosity varying from 86 to 93% were obtained at different internal phase fractions. PolyHIPEs were also prepared using Tween 20 as the emulsifier for comparison. It was found the polyHIPE using SDLC emulsifier (S-polyHIPE) showed higher porosity and consequent smaller foam density than that using Tween 20 emulsifier (T-polyHIPE), implying the gemini-surfactant can act as a novel type of promising emulsifier for the preparation of porous polyHIPEs. In addition, the adsorption performances of polyHIPEs were evaluated by adsorbing methylene blue (MB). At the same internal phase fraction, S-polyHIPE showed higher adsorption capacity and faster adsorption rate than T-polyHIPE. The adsorption data were analyzed by isotherm models and dynamic models, respectively. The results indicated that the adsorption occurs as a monolayer on the adsorbent surface with equal adsorption sites.

Double-shelled hollow structures possess unique properties in energy conversion/storage fields due to their higher surface area, larger contact region with the electrolyte and much shortened paths of charge transfer. In this work, CoMoSx@Ni-CoMoSx hollow polyhedron catalyst with a double-shelled cage-in-cage structure is prepared by a sequence of template-engaged synthetic processes. In the synthetic procedure, (NH4)2MoS4 is applied as a multifunctional vulcanizator, which can conveniently afford Mo and S elements at the same time. Noteworthily, by comparing with single-shelled hollow CoMoSx and Ni-CoMoSx polyhedrons, the double-shelled CoMoSx@Ni-CoMoSx polyhedron catalyst demonstrates superior catalytic properties in the reduction of triiodide in dye-sensitized solar cells. The solar cell with CoMoSx@Ni-CoMoSx based counter electrode exhibits a high power conversion efficiency of 9.30%, which is much higher than that of Pt (8.01%).

Novel MnO2-doped holey carbon materials were obtained by an efficient and facile synthetic method using chitosan, potassium hydroxide and potassium permanganate as the raw materials. The carbon framework with high specific surface area was derived from chitosan by carbonization and activation approach, afterwards, MnO2 nanorods were grown on the surface of porous carbon by one-step agitation method and the MnO2-doped holey carbon material was obtained. The scanning electron microscopy, energy-dispersive X-ray, transmission electron microscopy, X-ray diffraction, N2 adsorption-desorption measurements, Raman spectroscopy and X-ray photoelectron spectroscopy were employed to analyze the physicochemical characteristics of the MnO2-doped holey carbon materials. The electrochemical performance of these materials displayed well through relative tests including cyclic voltammetry, galvanostatic charge-discharge, and electrochemical impedance spectroscopy measurements in 6.0 M KOH solution. Especially, this as-obtained electrode material with the optimum ratio presented a high gravimetric capacitance (460F g−1 at 0.2 A g−1) and exceptional capacitance reservation (91.67% at 10 A g−1 over 10,000 cycles) in the three-electrode system with 6.0 M KOH solution as the electrolyte.

Rational design and controllable synthesis of multiple metal components according to chemical composition and morphology are essential for obtaining desirable electrochemical performance for efficient hydrogen production because of the morphology and synergistic effects of different components. Herein, we report an approach to facilely fabricate bimetal compounds with a well-defined hollow nanoprism structure using a self-templated strategy to synthesize novel hierarchical NiCo-layered double hydroxide (NiCo-LDH) nanosheets as precursors followed by in situ phosphorization. Among the as-synthesized products of different mole ratios of Ni/Co, the NiCo

Facile preparation of organohydrogel electrolyte integrated with good anti-freezing property, toughness, transparency, conductivity and thermoplasticity is important and still remains challenging. Novel conductive and tough poly(vinyl alcohol)/sodium alginate/glycerol (PVA/SA/Gly) composite organohydrogel electrolytes were obtained by a simple method in this paper. PVA and SA was firstly dissolved in a mixed solution of distilled water and glycerol and the PVA/SA/Gly organohydrogel was obtained by the freezing-thawing process, then PVA/SA/Gly organohydrogel was immersed into the saturated NaCl aqueous solution. During the soaking process NaCl would enter into the PVA/SA/Gly organohydrogel to increase the gel strength and conductivity. The PVA/SA/Gly organohydrogel electrolytes performed the high toughness with the tensile strength and elongation at break of 1.43 MPa and 558%, respectively. Moreover, the PVA/SA/Gly organohydrogel electrolytes behaved high transparency, anti-freezing property, conductivity and thermoplasticity due to the incorporation of glycerol. This paper provides a new preparation method for the high-performance organohydrogel electrolyte.

Transition metal chalcogenides with yolk-shell nanostructures are a family of promising electrocatalytic materials with complex interior construction and remarkable structural tenability. In this work, a sequence of yolk-shell transition metal sulfide nanospheres (Co-Ni-MoSx, Co-MoSx and Ni-MoSx) are prepared as superior Pt-free catalysts for dye-sensitized solar cells. This yolk-shell structure, consisting of a thin shell and an inner porous core, exposes more active sites and provides more contact regions between the electrolyte and catalyst. By comparing with the ternary Co-MoSx and Ni-MoSx nanospheres, the quaternary Co-Ni-MoSx nanospheres have advantages of the relatively larger surface area, favourable chemical composition, higher conductivity and excellent catalytic performance for expediting the reduction of I3− in solar cells. Particularly, as for Co-Ni-MoSx, a splendid power conversion efficiency of 9.76% is achieved under a standard irradiation, which is much better than that of Pt (8.24%).

A series of porous cubic nanomaterials have been prepared through a facile one-step selenylation process, in which Cu-Ni-Co, Ni-Co and Cu-Co Prussian-blue analog nanocubes transformed to Cu-Ni-CoSex, Ni-CoSex and Cu-CoSex nanocubes, respectively. Among these samples, the quaternary porous nanocubes (Cu-Ni-CoSex) proved to be the excellent bifunctional electrocatalysts in dye-sensitized solar cells and hydrogen evolution reactions. Under the standard irradiation, Cu-Ni-CoSex nanocubes exhibited a high power conversion efficiency of 9.74% in solar cells, which was much superior than that of Pt (8.19%). Cu-Ni-CoSex nanocubes also delivered superb hydrogen evolution performance in terms of a low overpotential (50.2 mV) under the current density of 10 mA cm−2 and a low Tafel slope (49.6 mV dec−1) in alkaline medium. The outstanding characteristics of Cu-Ni-CoSex nanocubes were benefited from their uniform sizes, porous morphologies, high surface area, low charge transfer resistances and good synergies among multiple elements.

In this research, pristine and boron-doped biochar/Al2O3 adsorbents for fluoride removal from aqueous solutions were prepared by employing chitosan (CS), poly(vinyl alcohol) (PVA), and AlCl3·6H2O as the raw materials. CS was dissolved in AlCl3·6H2O aqueous solution, and the CS/PVA aerogel was prepared by a freezing process. The biochar/Al2O3 was obtained by the carbonization process at high temperature. AlCl3·6H2O was used as both the solvent for CS and the source for Al2O3. The structure of biochar/Al2O3 was characterized by scanning electron microscopy, X-ray diffraction, and Raman spectroscopy. The adsorption performance of biochar/Al2O3 for fluoride was evaluated by the batch adsorption experiment. Furthermore, the effect of HBO3 cross-linking on the adsorption property of biochar/Al2O3 was studied. The results showed that the HBO3 cross-linking process would promote the adsorption performance of biochar/Al2O3. The adsorption kinetics and equilibrium properties are well-described with a pseudo-second-...

Due to the unique features including well-defined void space and high surface-to-volume ratio, non-noble metal catalysts with hollow structures have received intensive researches in dye-sensitized solar cells (DSSCs) and electrochemical water splitting. Herein, we prepare a series of cobalt-incorporated molybdenum sulfide hollow nanoboxes (denoted as Co-MoSx NBs) via a one-step fleet template conversion from cube-shaped Co-based zeolitic imidazolate framework-67 which precipitated without prolonged aged process. During above transformation, it is notable that the surface morphologies of nanobox can be effectively tailored by the proportion of MoS42−. The as-obtained Co-MoSx NBs with well-defined boxed structure and the appropriate doped ratio are developed as bifunctional catalysts for accelerating both reduction of I3− in DSSCs and hydrogen evolution reaction (HER). As expected, a high power conversion efficiency (9.64%) is achieved by Co-MoSx-1/3 NBs based DSSC under AM 1.5G irradiation, which is much preceded to that of Pt (8.39%). Meanwhile, the practical utilization of Co-MoSx-1/3 NBs for HER yields a low onset overpotential (35 mV) and a small Tafel slope (61.4 mV decade−1) in alkaline medium.

N-Isopropylacrylamide (NIPAM) was successfully grafted on reduced graphene oxide (RGO) by free radical polymerization and characterized by attenuated total reflection Fourier transform infrared (ATR-FTIR) spectroscopy, transmission electron microscope (TEM) measurements, thermogravimetric analysis and ultraviolet–visible transmission spectroscopy. The synthesized poly(N-isopropylacrylamide)–reduced graphene oxide (PNIPAM–RGO) was used to improve the properties of polysulfone (PSF) membranes with different PNIPAM–RGO weight fractions. The structure and properties of PNIPAM–RGO/PSF membrane were characterized by X-ray photoelectron spectroscopy, scanning electron microscopy, atomic force microscope, contact angle and tensile testing. The water permeability, self-cleaning recovery rate and water flux decline factor were tested. The blend membrane with 0.4 wt% PNIPAM–RGO possessed the optimal rejection and exhibited an impressive self-cleaning recovery rate and fracture strain of 98.6 and 72.2%, showing a 67.4 and 76.5% enhancement compared to that of pure PSF membrane (58.9 and 40.9%), respectively. Meanwhile, the water flux decline factor decreased from 21.0 to 7.8%. The drastic change of permeability to aqueous solution, observed around lower critical solution temperature of PNIPAM–RGO, proved the thermal sensitivity of the blend membrane. The NIPAM grafted onto RGO by free radical polymerization and utilizing the advantages of both PNIPAM and RGO, which was used as an additive in the membrane, and very hard to lose during the membrane formation and application. The resulting membrane exhibited a significant increase in self-cleaning recovery rate, hydrophilicity, mechanical strength and thermosensitivity.

The facile preparation of hydrogel electrolyte with high strength, healing ability and thermoplasticity is important and still remains a great challenge. In this paper, a novel way for the preparation of poly(vinyl alcohol) (PVA) supramolecular hydrogel electrolyte was presented. The PVA hydrogel electrolyte was prepared via the hydrogen bonding and salting-out effect. The high performance PVA-NaCl-glycerol hydrogel electrolyte could be obtained by the doping of glycerol and NaCl into PVA aqueous solution and storing at room temperature for 2.0 h. The crystallinity, thermal and mechanical properties of PVA-NaCl-glycerol hydrogel electrolyte were characterized by Fourier transformed infrared spectroscopy, X-ray diffraction measurement and tensile testing, respectively. The hydrogel forming mechanism was discussed. The PVA-NaCl-glycerol hydrogels performed the high toughness with the tensile strength and elongation at break of 0.57 (±0.02) MPa and 575 (±29)%, respectively. The conductivity of PVA-NaCl-glycerol was as high as 92.5 (±0.18) mS/cm. The PVA-NaCl-glycerol hydrogel electrolyte behaved the excellent heat healing ability and thermoplasticity. These properties of PVA-NaCl-glycerol are related to the role of glycerol and NaCl. This paper provides a new preparation method and structure design idea for the high performance hydrogel electrolyte.

High temperature carbon dioxide electrolyzers are expected to play a key role on carbon-neutral energy cycle. Here we report a novel composite, namely perovskite SrFeO3−δ with impregnated Ni nanoparticles, as an advanced cathode materials for solid oxide electrolysis cells (SOECs). The XRD, SEM and TEM together indicate that the homogeneously distributed Ni nanoparticles on SrFeO3−δ substrate create sufficient and active triple-phase boundary (TPB) for electrochemical carbon dioxide splitting. Electrochemical measurements show that this tailored SrFeO3−δ cathode demonstrates better performance, and then exhibits long-term stability after 100 h operation and 8 redox cycles.

Nitrogen and boron co-doped activated carbon (BKACS) was synthesized through the carbonization, KOH activation and subsequently hydrothermal doping reaction process with chitosan as the renewable carbon source. The prepared samples were characterized by XRD, SEM, Raman, XPS and BET for their structure, morphology, specific surface area and elemental composition, respectively. The obtained BKACS has a specific surface area of 1129.6 m2 g−1, with high conductivity and capacitive character. The BKACS was applied as the electrode material to fabricate the electrochemical double-layer supercapacitor. The supercapacitor performed a high specific capacitance of 316 F g−1 at 0.2 A g−1 in a three-electrode system in the 6 M KOH electrolyte and excellent cycling stability with a capacitance retention of 94.08% after 10,000 cycles at 10 A g−1. The attractive supercapacitor performance of the BKACS material has the high power density, excellent cycling life, and environmental friendliness, making it potentially a promising replaceable function for future energy storing device.

Box-structured nanomaterials with complicated surface texture, whose morphologies can be adjusted through changing mass ratios of reactants, are attractive in the field of electrochemical energy conversion. Herein, we report the shape-controllable synthesis of MoS2 doped cobalt iron sulfide (Co-Fe-MoSx) hollow nanoboxes with three different mass ratios of cobalt iron Prussian-blue-analog (Co-Fe PBA) nanocubes to (NH4)2MoS4 and their applications in dye-sensitized solar cells (DSSCs). As the increment of MoS42− in system, the surface of Co-Fe-MoSx became rough with bushy embedded nanosheets. Benefiting from the three-dimensional nanostructure with more exposed edge sites and appropriate doped ratio, the Co-Fe-MoSx-2 hollow nanoboxes performed rough shells, well-defined interior voids, large specific surface areas and outstanding catalytic actives. By contrast, the sulfide of Co-Fe PBA (Co-Fe-S) and bare MoS2 showed bad morphology and poor catalytic performance. It is notable that the DSSC with Co-Fe-MoSx-2 showed a much higher power conversion efficiency (PCE) of 9.63% than that of Pt based cell (8.23%) under AM 1.5G irradiation.

A novel magnetic bioadsorbent beads composed of Fe3O4, chitosan, and Al(OH)3 (Fe3O4/CS/Al(OH)3) was synthesized by a modified solvothermal and in-situ reaction. The composite adsorbent was characterized by Fourier-transform infrared spectroscopy, X-ray diffraction, scanning electron microscopy, energy dispersive X-ray spectroscopy, and vibrating sample magnetometer, respectively. Adsorption toward F− onto Fe3O4/CS/Al(OH)3 was investigated as a function of Fe3O4 concentration, initial solution pH, adsorbent dosage, initial fluorion concentration, co-existing ions in water and initial temperature. The addition of Fe3O4 could enhance the adsorption properties of CS/Al(OH)3. The saturated adsorption capacity of magnetic Fe3O4/CS/Al(OH)3 calculated from the Langmuir isotherm model was 76.63 mg/g at 298 K. The adsorption isotherm of F− followed Langmuir isotherm model and the adsorption kinetics fitted better to the pseudo-second order kinetic model. The influence of temperature confirmed that the adsorption was spontaneous and endothermic. The magnetic Fe3O4/CS/Al(OH)3 beads could be easily separated from water under a low magnetic field.

In this work, Si-doped cross linked carbon nanofibers (Si/CNF) were prepared by electrospinning polyacrylonitrile (PAN) solutions containing polyhedral oligomeric silsesquioxane (POSS) as Si source, followed by thermal treatments. Scanning electron microscope (SEM) observations showed the smooth surfaces of pure PAN nanofibers, while PAN/POSS nanofibers with obviously rough or porous surfaces were obtained with relatively high POSS content. X-ray diffraction (XRD) identified the presence of POSS in the composite nanofibers. After thermal treatments, cross linked Si/CNFs with various morphologies were obtained. Energy-dispersive X-ray (EDX) and X-ray photoelectron spectroscopy (XPS) analyses confirmed the successful incorporation of Si into CNFs. Raman spectra suggested the degree of carbon ordering of Si/CNFs reduced slightly when compared with pure CNF. The obtained nanofibers exhibited typical performances of electric double-layer capacitors (EDLC). The specific capacitance of Si/CNF showed a moderate increase with POSS content and reached a maximum of 175 F/g at 1 A/g with PAN:POSS equal to 100:5. Meanwhile Si/CNFs exhibited excellent cycling stability after 1000 cycles. The influence of POSS on the capacitive performance might be attributed to the combined effects of evolution of morphology, conductivity and surface properties of Si/CNFs.

A Polyhedral oligomeric silsesquioxane (POSS) modified Ziegler-Natta catalyst is reported to synthesize the weakly entangled ultra-high molecular weight polyethylene at a high temperature and with a high activity. Incorporation of POSS can form numbers of aggregates with a mean size of 48 nm adsorbing on the surface of SiO 2 . The structure of nanoaggregates is evidenced by the experiments and theoretical calculations where one POSS can coordinate with multiple MgCl 2 molecules serving as an electric donor to the further immobilized TiCl 4 . The catalyst is thus featured by two distinct active regions positioned in the POSS/MgCl 2 nanoaggregates and δ -MgCl 2 , respectively. The former regions present extremely low activity on ethylene polymerization, which function as horizontal separators for isolating the active TiCl 4 sites and the growing chains. This catalyst exhibits an exceptional activity ( i.e. 1.3 × 10 6 gPE mol Ti −1 h −1 bar −1 ) for the synthesis of weakly entangled polyethylene at 60 °C.

Taking advantages of excellent adhesion and insulating properties, polymer-based thermal interface materials have been widely used in electrical and electronic industry. However, applications was limited due to the existence of high interfacial resistance and poor mechanical properties resulted from poor dispersion and weak interfacial adhesion of thermal conductive fillers in the polymer matrix. Herein, different sizes of aluminum oxide microparticle was used as thermal conductive fillers to fabricate a series of high thermal conductive epoxy composites, and the effect of fillers loading ratio on the properties of thermal conductive, mechanical, thermal stability was further analyzed. The optimum composite exhibits a high thermal conductivity (1.91 ± 0.02 W·m−1·K−1) at a loading ratio of 1: 2 (20-μm: 70-μm, mass ratio), which is equivalent to a thermal conductivity enhancement of 950% in comparison with pure epoxy resin. The outstanding properties of the as-prepared composite is mainly attributed to the effective conductive network formed by different size fillers that the smaller particles act as a bridge to connect the larger one. This work has proved by Agari model that combining different sizes Al2O3 as fillers is a workable way to obtain composite with high thermal conductivity and it is expected to provide a reliable route for the preparation of thermally conductive composites with different particle sizes.

Adhesion and stretchable hydrogel electrolytes have emerged as an ideal candidate in the fabrication of flexible all-solid-state supercapacitor. However, the conventional hydrogel electrolyte would inevitably deteriorate or even deactivate after mechanical damage (stretching and cutting) or dehydrating. As an alternative to overcome these limitations, we designed a dynamic elastic molecular double network (DN) hydrogel electrolyte consisting of poly(vinyl alcohol) (PVA) and poly(acrylic amide-co-2-acrylamido-2-methylpropane sulfonic acid) (P(AM-AMPS)) networks. Glycerin was introduced into the PVA/P(AM-AMPS) system to enhance the inter-chain physically-crosslinked network. This DN hydrogel electrolyte exhibited remarkable stretchability (over 894%), strong adhesion (37.00 kPa to carbon materials) and high ionic conductivity (3.85 S m−1). In particular, the dynamic physically-crosslinked network endowed hydrogel electrolyte eminent mechanical tolerance. The toughness of hydrogel kept stable in 10 times 500% strain loading–unloading tensile test. Along with the CNT electrodes, a highly flexible all-solid-state supercapacitor was prepared by using our developed DN hydrogel as electrolyte. This hydrogel-based supercapacitor exhibited high capacitance (85.25 mF cm−2 at a current density of 0.5 mA cm−2). More importantly, benefiting from the unique network structure of hydrogel electrolyte, a steady bonding interface between electrode and electrolyte was constructed. Electrochemical performance of supercapacitor could be maintained in different working conditions. The capacitance of a device was stable upon stretching (200% strain) or bending (angle of 0–180°). In addition, hydrogel based supercapacitor could be resumed after dehydrating or cutting by accident. Our results provide a new slight into multifunctional all-solid-state supercapacitor preparation. We hope this hydrogel will promote the development of wearable energy storage.

Transition metal chalcogenides with hollow nanostructures have been considered as promising substitutes as precious metal electrocatalysts for energy conversion and storage. We synthesized NiCo2S4 double-shelled ball-in-ball hollow spheres (BHSs) via a simple solvothermal route and applied them in both dye-sensitized solar cells (DSSCs) and hydrogen evolution reactions (HERs) at the same time, which were clean and sustainable ways to convert energy. Benefiting from their remarkable structure features and advantageous chemical compositions, NiCo2S4 BHSs composed of tiny crystals possessed large surface area, well-defined interior voids, and high catalytic activity. The DSSC with NiCo2S4 BHSs under 100 mW cm–2 irradiation possessed a power conversion efficiency of 9.49% (Pt, 8.30%). Besides, NiCo2S4 BHSs as a HER catalyst also possessed a small onset overpotential (27.9 mV) and a low overpotential (89.7 mV at 10 mA cm–2) under alkaline conditions. Therefore, this work offers a sensible strategy to synthesiz...

Single-layer carbon-based dots (SCDs) were chosen as a model to investigate the effect of the C-related dangling bonds with spin S=1/2 and functional groups on the electrochemiluminescent (ECL) and fluorescent (FL) properties of CDs. The C-related dangling bonds and functional groups of SCDs were tuned by chemical reduction with NaBH4 . There have several main findings via investigating the ECL and FL properties of SCDs before and after the chemical reduction. First, the FL and ECL of CDs are highly dependent on their concentration, and luminescent resonance energy transfer is observed in ECL studies when the concentration of CDs is high. Second, the ECL activity of CDs is greatly enhanced as the C-related dangling bonds increase, proving that the ECL of CDs originates from the C-related dangling bonds. Third, the FL of CDs is the synthesis of the inner FL originated from the contained isolated sp2 units and the defect FL from the C-related dangling bonds. The inner FL of CDs is enhanced greatly by removing the carboxyl groups, while the defect FL is increased slightly due to the increased C-related dangling bonds. We believe this study would promote our understanding in the ECL and FL mechanisms of CDs, advancing the applications of CDs based on their ECL and FL properties.

A novel low-cost adsorbent named chitosan/Al(OH)3·(CS/Al(OH)3) bead was successfully prepared by employing AlCl3·6H2O aqueous solution as the solvent for CS. The CS/Al(OH)3 beads were used for fluoride removal from water. The beads were synthesized using the chitosan and aluminum chloride with the mass ratio of 2:1 as the precursor and in situ generation of aluminum hydroxide sorbents in sodium hydroxide solution. Then, the beads were washed with distilled water to neutral and freeze dried. The sorbents were characterized using scanning electron microscopy (SEM), energy dispersive X-ray spectrometry (EDX), Fourier transform infrared spectrometry (FTIR), and X-ray diffractometry (XRD), respectively. Batch adsorption experiments were conducted to evaluate the parameters that affected the defluoridation capacity. The influencing parameters including pH, co-existing ions in water and initial temperature of the adsorption process were studied. The influence of temperature confirmed that the adsorption was spontaneous and endothermic. The adsorption isotherm of fluoride followed Langmuir isotherm model and the sorption kinetics was more suitable for pseudo-second-order kinetic model. The defluoridation capacity of chitosan/Al(OH)3 calculated using Langmuir model was 23.06 mg/g (293 K, pH 4). The experimental results showed that the CS/Al(OH)3 bead adsorbent is promising for the fluoride adsorption.

Yolk–shell nanocages possessing complex internal structure and excellent structural tenability are advantageous for the preparation of advanced catalysts. Due to outstanding features such as superior electrical, magnetic, optical and catalytic properties, non-noble metal materials with hollow nanostructures have been considered potential substitutes for highly active and stable abundant noble-metal electrocatalysts. In this study, the as-prepared CoS2–C@CoS2 yolk–shell nanocages were applied in both dye-sensitized solar cells (DSSCs) and hydrogen evolution reactions (HERs). Due to the remarkable structural features and advantageous chemical compositions, CoS2–C@CoS2 yolk–shell nanocages comprising tiny crystals possessed large surface area (161 m2 g−1), well-defined interior voids, excellent conductivity and high catalytic activity. The DSSC with CoS2–C@CoS2 achieved a high power conversion efficiency (PCE) of 9.32% under AM 1.5 G irradiation, and it outperformed the DSSC with Pt (8.24%). Besides, CoS2–C@CoS2 as a kind of HER catalyst also exhibited a low onset overpotential of 19.0 mV, small Tafel slope of 51.9 mV dec−1 and low overpotential of 79.1 mV at a current density of 10 mA cm−2 under acidic conditions (0.5 M H2SO4).

In this study, a series of novel quaternized poly(vinyl alcohol)/chitosan/molybdenum disulfide (QPVA/CS/MoS2) anion exchange membranes (AEMs) were prepared for direct methanol alkaline fuel cell (DMAFC). The composite membrane was synthesized by adding different amounts of MoS2 nanosheets (0, 0.1, 0.2, 0.5 and 1wt%) into QPVA/CS mixture solution and using the solution casting method. The crystallinity, thermal and mechanical properties, ion conductivity and resistance to methanol of the QPVA/CS/MoS2 membranes were characterized by X-ray diffraction, thermogravimetric analysis, tensile testing, ion exchange capacity, and methanol permeability measurements, respectively. The MoS2 was homogeneously dispersed in the membranes. The mechanical strength of the composite membranes was enhanced with the addition of MoS2. With the addition of 1.0wt% MoS2, the QPVA/CS/MoS2 composite membrane has the lowest methanol permeability of 0.210×10-7cm2·s-1. This study confirmed that the novel QPVA/CS/MoS2 membrane would be a potential candidate for the application in DMAFCs.

The development of highly efficient electrocatalysts has attracted increasing attention in the field of electrochemical energy conversion. Therefore, we report a simple self-template method to construct Co-Sn-X (X = S, Se, Te) nanocages through the anion exchange reaction of CoSn(OH)6 nanocubes with chalcogenide ions under mild solvothermal conditions. Benefiting from advantageous compositional features and well-designed architectures, the obtained Co-Sn-X (X = S, Se, Te) nanocages display enhanced electrocatalytic activity for dye-sensitized solar cells (DSSCs) and the oxygen evolution reaction (OER) in an alkaline electrolyte. Remarkably, the Co-Sn-Se nanocages as the counter electrode (CE) catalyst deliver a prominent power conversion efficiency (PCE) of 9.25% for DSSCs compared with Pt CE (8.19%). Furthermore, when used as an OER catalyst, the Co-Sn-Se nanocages also exhibit outstanding electrocatalytic activity in terms of their low overpotential of 304 mV at the current density of 10 mA cm-2 and long-term stability in 1.0 M KOH solution. This work provides wide prospects for the rational design and synthesis of high-performance transition metal chalcogenide-based electrocatalysts for future energy conversion systems.

A green and facile fermentation method for the synthesis of carbon based dots (CDs) has been developed for the first time. The fluorescence (FL) properties of the obtained CDs could be tuned by changing the kind of microbes. For instance, the fermentation of leaves with Bacillus subtilis produces red emission CDs, which show great application potential in bioimaging. The formation mechanism and the FL mechanism of the CDs have been well discussed.

A novel series of ternary compounds, namely cobalt iron selenide/sulfide nanocubes, are successfully synthesized as counter electrode (CE) materials for dye-sensitized solar cells (DSSCs), which deliver excellent performances. Homogeneous cobalt iron Prussian-blue-analog (PBA) nanocubes are prepared as the templates and are subsequently dealt with selenation/sulfidation processes via hydrothermal methods. Owing to their unique morphology, porous structure, high surface area, small charge transfer resistance and high diffusion coefficient, the Co-Fe-Se/S nanocubes possess high catalytic activity and excellent conductivity, which are tested and verified by electrochemical measurements. Meanwhile, cobalt iron selenide/sulfide nanocubes CEs achieve high efficiencies of 9.58% and 9.06%, respectively, which are both higher than that of Pt CE (8.16%). All these prominent merits make them outstanding and promising participants among Pt-free CE materials of DSSCs with lower production costs and higher power conversion efficiency.

Development of bio-based hydrogels with good mechanical properties is of great importance for their excellent biocompatibility and biodegradability. In this paper, chitosan (CS) based double network (DN) hydrogel was prepared by dissolving CS in AlCl3·6H2O aqueous solution instead of acetic acid solution. After dissolving acrylic amide (AM), acrylic acid (AA), N, N'-methylenebisacrylamide and 2-hydroxy-4'-(2-hydoxyethoxy)-2-methylpropiophenone were added into the CS/Al3+ solution and the CS/PAMAA-Al3+ DN hydrogel was prepared by UV polymerization. The hybrid physical and chemical crosslinked network hydrogels were prepared. The tensile and compression properties of CS/PAMAA-Al3+ DN hydrogel were studied. The results showed that the CS/PAMAA-Al3+ DN hydrogels have high toughness, stretch-ability, and excellent shape recovery properties. The CS/PAMAA-Al3+ DN hydrogel could show the tensile strength of 0.54MPa and elongation at break of 2203.7%. These properties arise from the dynamic ionic interaction between Al3+ and CS/PAMAA macromolecular chains.

Solid oxide electrolysis cells with La 0·75 Sr 0·25 Cr 0·5 Mn 0·5 O 3-δ (LSCM) cathode can electrolyze CO 2 to generate chemical fuels. Nevertheless, the cathode performance is limited by its electrocatalytic activity. In this work, metal nanoparticles including Ni, Cu and NiCu metals are successfully impregnated in LSCM electrode to improve its activity. XRD, XPS, SEM and TEM together confirm the metal nanocatalysts are homogeneously distributed on LSCM backbone and therefore create active electrochemical interface for CO 2 splitting. Electrical properties of LSCM with impregnated metal nanoparticles are investigated and correlated to electrode performances. Electrochemical measurements show that the NiCu-LSCM demonstrates the optimum performance without degradation after operation for ∼100 h and ∼10 redox cycles. It is believed that the enhanced performance of CO 2 electrolysis may be attributed to the synergetic effect of metal nanocatalyst and LSCM ceramic electrode.

The development of highly active and stable earth-abundant electrocatalysts to reduce or eliminate the reliance on noble-metal based ones for hydrogen evolution reaction (HER) over a broad pH range remains a great challenge. Herein, hierarchical porous Co9S8/N-doped carbon@MoS2 (Co9S8/NC@MoS2) polyhedrons have been synthesized by a facile hydrothermal approach using highly conductive Co/NC polyhedrons composed of cobalt nanoparticles embedded in N-doped carbon matrices as both the structural support and cobalt source. The Co/NC polyhedrons were prepared by direct carbonization of Co-based zeolitic imidazolate framework (ZIF-67) in Ar atmosphere. Benefiting from the prominent synergistic effect of N-doped carbon enhancing the conductivity of the hybrid, MoS2 and Co9S8 providing abundant catalytically active sites as well as the well-defined polyhedral structure promoting mechanical stability, the as-synthesized Co9S8/NC@MoS2 shows excellent HER activity and good stability over a broad pH range, with onset ...

Three metal-free push–pull type organic dyes QX19 – 21 based on indeno[1,2- b ]indole donor have been synthesized for dye-sensitized solar cells (DSSCs). In order to obtain good cell performance, an ethynylene linker was inserted into the dye skeleton to extend π-conjugated planar rigid structure and three hexyl groups were involved to prevent dye aggregation. The dyes QX19 and QX20 employing phenylene and thiophene as the π-bridges were designed as a D–π–A structure. As for the dye QX21 , a benzothiadiazole was inserted as the secondary acceptor to construct as a D–A–π–A structure. All three dyes based cells exhibited high photovoltages and good DSSC performances. A high PCE of 7.99% was obtained by the dye QX21 under AM 1.5G irradiation. Especially, the co-sensitization of QX21 with QX20 achieved the further improved PCE up to 8.37%.

High tough poly(vinyl alcohol) (PVA) hydrogels were prepared by repeated freezing/thawing processes and subsequently soaking in saturated NaCl aqueous solution. The PVA hydrogels were characterized via tensile testing, differential scanning calorimetry and scanning electron microscopy respectively. The results showed that during soaking in NaCl aqueous solution the PVA chain-entanglement network was formed and the water was included into the PVA chain-entanglement network. The tensile strength and elongation at break of PVA hydrogel firstly increased with the prolongation of immersing time and then decreased with the immersing time beyond 30 min. By this way the tensile strength and elongation at break of PVA hydrogel could reach up to 1.61 (±0.24) MPa and 631 (±80)%, respectively. This tough PVA hydrogel was prepared at the absence of chemical crosslinker and thus might be considered as a favourable candidate for tissue engineering applications.

Ternary nickel cobalt selenide (Ni-Co-Se) alloy based hollow microspheres have been successfully synthesized via a simple one-step hydrothermal route by controlling different hydrothermal temperatures. The prepared samples were divided by reaction temperatures (140, 160, 180 and 200 °C) and named as Ni-Co-Se-140, Ni-Co-Se-160, Ni-Co-Se-180 and Ni-Co-Se-200, respectively. With the temperature increasing, the hollow microspheres formed at the lower temperature and broke at the higher temperature, and the sample Ni-Co-Se-180 exhibited the most regular and homogeneous hollow microspheres with a size of 1.5–2.5 μm. Moreover, the Ni atomic ratios in Ni-Co-Se alloys increased with the temperature rising. The prepared Ni-Co-Se alloys were used as counter electrode (CE) catalysts for dye-sensitized solar cells (DSSCs). A series of electrochemical tests all verified Ni-Co-Se alloy based CEs had superior electrocatalytic activities and Ni-Co-Se-180 CE displayed the largest current density, lowest overpotential and smallest charge-transfer resistance than the other CEs and Pt CEs. Benefiting from their unique morphologies and surface structures, the cells with the Ni-Co-Se-160, Ni-Co-Se-180 and Ni-Co-Se-200 based CEs achieved high efficiencies of 8.39%, 9.04% and 8.72%, respectively, which were all higher than that of Pt CE (8.07%).

Four novel T-shaped metal-free organic sensitizers QX22 – 25 based on triphenylamine and indoloquinoxaline have been successfully designed and synthesized as a (D) 2 –A–π–A type structure. These dye sensitizers have two triphenylamine donors attaching on an indoloquinoxaline-based subordinate acceptor. Different π-bridges (thiophene and furan) and acceptor/anchoring groups (cyanoacrylic acid and 2-(1,1-dicyanomethylene)rhodanine) were involved to tune the photoelectrical properties. Their optical, electrochemical, and photovoltaic properties as well as the DFT calculations have been systematically investigated, indicating these four dyes are all capable as photosensitizers. A highest power conversion efficiency up to 7.09% with a J sc of 12.9 mA cm −2 and a V oc of 817 mV has been achieved by the dye QX23 with a furan π-bridge and a cyanoacrylic acid acceptor/anchoring group, indicating it is a promising strategy to construct efficient (D) 2 –A–π–A type sensitizers by incorporating indoloquinoxaline and triphenylamine.