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Heteroatom doped porous carbon materials have great application prospects in supercapacitors. In the present study, an approach of preparing N-doped porous carbon (NPC) was proposed from porous poly(resorcinol-formaldehyde-melamine) monoliths which were prepared by high internal phase emulsion (HIPE) template. Melamine was dissolved in the external phase and copolymerized, acting as the N source and porous structure regulator to provide micropore-dominant NPCs. The structure, morphology, specific surface area (SSA), and chemical composition of the samples were systematically studied. With melamine content increasing, N-doping content in NPC increased while the SSA of NPC increased at first and then decreased. When the content of N is 8.42 ​wt%, the obtained NPC showed the highest SSA of about 1670 ​m2 ​g−1. Furthermore, high N doping content could improve the electronic conductivity and provide additional pseudocapacitance of NPC. Under the combined influences of proper N content and high porosity, the prepared NPC electrodes revealed excellent specific capacitance (228.0 ​F ​g−1 at 1.0 ​A ​g−1), favorable circling stability, and prominent rate capability in a three-electrode system with 6 ​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 NiCo2-B-P nanoprisms that integrate the advantages of a hollow structure, an optimal Ni-Co synergistic effect, and a unique B-doped CoP/Ni2P bimetallic phosphide derived from NiCo-LDH nanosheets exhibit excellent hydrogen evolution reaction (HER) activity in an alkaline solution at 10 mA cm-2 with the lowest overpotential of 78 mV and long-term stability. This study may offer an appropriate structure and compositional design of bimetallic alkaline HER catalysts.

Hydrogels are important for stretchable and wearable multifunctional sensors, but their application is limited by their low mechanical strength and poor long-term stability. Herein, a conductive organohydrogel with a 3D honeycomb structure was prepared by integrating carbon nanotubes (CNTs) and carbon black (CB) into a poly(vinyl alcohol)/glycerol (PVA/Gly) organohydrogel. Such a nanocomposite organohydrogel is built on a physical cross-linking network formed by the hydrogen bonds among PVA, glycerol, and water. CNTs and CB had an add-in synergistic impact on the mechanical and electrical performances of the PVA/Gly organohydrogel because of the distinct aspect ratios and geometric shapes. The prepared organohydrogel integrated with a tensile strength of 4.8 MPa, a toughness of 15.93 MJ m-3, and flexibility with an elongation at break up to 640%. The organohydrogels also showed good antifreezing feature, long-term moisture retention, self-healing, and thermoplasticity. Sensors designed from these organohydrogels displayed high stretching sensitivity to tensile strain and temperature, with a gauge factor of 2.1 within a relatively broad strain range (up to ∼600% strain), a temperature coefficient of resistance of -0.935%·°C-1, and long-term durability. The sensors could detect full-range human physiological signals and respond to the change in temperature, which are highly desired for multifunctional wearable electronic devices.

Carbon-based materials are attractive in heterogeneous catalysis. In addition to be an ideal support for catalytic active species, carbon can form a protecting layer for non-noble metal nanoparticles (NPs) to prevent them from being oxidized. However, the synthesis of carbon supported non-noble metal NPs, with an even distribution of these transition metal NPs coated by a carbon shell, is still challenging. In this work, carbon supported metallic Co NPs coated by a graphitic carbon layer (C/Co@C) was successfully synthesized via calcinating of Co-MOF-74 at 1000 °C. The highly selective semi-hydrogenation of aromatic alkynes with NaBH4 to produce aromatic alkenes was realized over the as-obtained C/Co@C, in which the graphitic carbon layer acts like a “one-way valve” to allow BH4− to flow through, while preventing the larger size aromatic alkyne from entering the carbon shell to avoid its excessive hydrogenation. This work highlights the important role of using MOFs as precursor to prepare stable supported metal NPs for heterogeneous catalysis.

Biomass carbon materials which have the merits of green, low cost and renewability, can be obtained from sodium alginate (SA) beads crosslinked by polyvalent metal ions. SA beads are possible to be obtained using diammoniums as the crosslinking agents. In this work, N-O codoped porous carbon (NO-PC) was prepared from SA beads crosslinked by diammoniums through the electrostatic interaction between ammonium cations and carboxylate groups of SA chains. The using of diammoniums as the crosslinkers achieved N doping into NO-PC. Scanning and transmission electron microscope observations revealed that NO-PC possessed hierarchically porous characteristic. X-ray photoelectron spectroscopy identified the successful N-O codoping. Both the species and concentration of diammoniums strongly affected the porous structure, surface area and electrochemical performance of NO-PC. N2 adsorption-desorption results of NO-PC indicated that the highest surface area was up to 3794 m2/g. The NO-PC based supercapacitors showed high specific capacities up to 269.0 F/g at 1 A/g and excellent cycling stability (92.09% after 5000 cycles at 5 A/g). The energy density of the symmetric supercapacitor was up to 18.9 Wh/kg at a power density of 1380 W/kg with a voltage window of −1.4–0 V.

The work reported the preparation of hierarchically porous carbons (HPCs) with adjustable pore architectures using high internal phase emulsion (HIPE) template with the presence of polyaniline-coated carbon nanotubes (PANI-CNTs). PANI-CNTs were obtained via in situ polymerization of aniline in CNT suspension as confirmed by scanning electron microscope (SEM) and thermogravimetric analysis (TGA). Porous polydivinylbenzene (PDVB) monoliths were prepared by polymerizing the continuous phase of HIPE with PANI-CNTs dispersed in the internal phase. After carbonization and activation, HPCs with variable pore architectures were obtained. As observed by SEM, the PANI-CNTs showed notable influence on the pore architectures of PDVBs and HPCs. The void size of PDVB precursor reduced with the increase of the mass ratio of PANI to CNT, as well as the content of PANI-CNTs. Nitrogen adsorption/desorption measurements indicated the coexistence of mesopores and micropores, namely, hierarchical pores. The specific surface area (SSA) of HPC increased along with the content of PANI-CNTs from 1893 to 2392 m2/g. The capability of HPCs as the electrode material of supercapacitor was evaluated via electrochemical tests. The results indicated that the HPC with optimized pore architecture showed a higher specific capacitance (168.6 F/g) than the contrast sample (130.9 F/g) at 1 A/g. The better capacitance performance of HPC obtained with the presence of PANI-CNTs could be attributed to the reasonable hierarchical pores, higher SSA, and higher graphitization degree.

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.

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.

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.

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.

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.

Four new metal-free organic dyes QX15 – 18 based on indeno[1,2- b ]indole have been successfully designed and synthesized. These D–π–A type dyes consist of an indeno[1,2- b ]indole donor and a benzene or thiophene π-bridge. In an attempt to tune their photoelectric properties, the effects of different acceptor groups including cyanoacrylic acid, rhodanine-3-acetic acid, and 2-(1,1-dicyanomethylene)rhodanine (DCRD) have been investigated. The dye QX15 with a cyanoacrylic acid acceptor exhibited a highest V oc of 813 mV and a high J sc of 11.0 mA cm −2 , generating a highest power conversion efficiency of 6.29%. Meanwhile, the dye QX18 with a DCRD acceptor and a thiophene π-bridge showed a significantly improved J sc of 11.9 mA cm −2 , which could be attributed to its red-shifted absorption spectra and high molar absorption coefficient.

In consideration of the strong oxidizing power of hypochlorite (ClO−), which could cleave C N moiety, a cyclometalated iridium (III) complex (Ir-Ts) modified hydrazide group as the response unit was synthesized to sensitively and selectively detect ClO− under neutral condition. Upon addition of ClO−, a 21-fold emission enhancement at 574 nm was observed and phosphorescent product was formed due to the cleavage of C N moiety. The probe Ir-Ts displayed rapid response (

Surfactants play an essential role in the field of metal corrosion inhibition by adsorption. In this work, novel Schiff base-based cationic Gemini surfactants were synthesized, purified, and characterized, which particular chemical structures benefit to adsorbing on the metal surface and thus restricting metal corrosion. The corrosion inhibiting mechanism of the synthesized surfactants was researched by electrochemical impedance spectroscopy, potentiodynamic polarization, and weight loss measurements. It was found that the surfactants behave as mixed-type inhibitors, and the adsorption follows Langmuir isotherm. SG-16 presents the best anti-corrosion effect; its corrosion inhibition efficiency reaches 93.5% for Q235 carbon steel and 83.38% for printed circuit boards. Scanning electron microscopy and X-ray photoelectron spectroscopy were applied to investigate the sample's surface morphology, which showed that there were surfactants, oxide, and very few corrosion traces on the sample's surface. These experimental results show that the novel Gemini surfactants are efficient corrosion inhibitors for metal.

Novel rosin-based Gemini surfactants (RGS-n) are synthesized from dehydroabietylamine and four different N, N-dimethyl long-chain aliphatic amines. Compared with traditional surfactants, the critical micelle concentration (CMC) of RGS-n is reduced by 2 to 3 orders of magnitude. The three-ring skeleton of dehydrogenated rosin can improve the emulsification of RGS-n. Besides, the Kraff points of RGS-n are less than 0 °C, indicating the availability of RGS-n at low temperature. RGS-n exhibits a better cleaning effect through the combination of electrostatic interaction with carboxyl groups of rosin and the emulsification of RGS-n. The smaller presence of residual rosin on printed circuit boards (PCBs) after cleaning with RGS-n indicates higher cleaning performance of RGS-n. The effect of the length of the hydrophobic chain on cleaning efficacy is analyzed for PCBs. Higher cleaning efficacy is observed at RGS-14. This work has specific research significance for Gemini surfactant application as a cleaning agent in industrial circuit board cleaning.

Carbon materials with hierarchical porous structure and heteroatom-doping have gained extensive attention as promising electrode for supercapacitors. In this study, we report a facile approach which involves only one step of calcination and washing treatment to prepare nitrogen-doped carbon material with tunable pore structure. This carbon material was derived from chitosan employing the blend of potassium nitrate and hexahydrate magnesium nitrate as the active agent. By adjusting the calcination temperature and active agents, the morphology and pore structure of the material can be effectively controlled. By means of this approach, the three-dimensional hierarchical porous carbon possesses a large specific surface area of 922 m2 g−1, and abundant nitrogen and oxygen functional groups. Benefiting from these advantages, the final product shows high specific capacitance of 225.3 F g−1 in a three-electrode system at 1 A g−1, good cycle stability with 88% capacity retention after 10000 cycles at 5 A g−1. Additionally, the constructed symmetric two-electrode supercapacitor shows remarkable specific energy of 10.46 Wh kg−1 with the specific power of 500.08 W kg−1. It also showed excellent electrochemical performance in PVA/KOH hydrogel electrolyte with 70.8 F g−1 at the current density of 1 A g−1.

Tubular-structured nanomaterials with tailorable crystal structures and shell architectures whose properties can be tuned without changing their chemical compositions are attractive in electrochemical energy conversion and storage fields. Herein, we report the fabrication of tubular-structured orthorhombic CoSe2 (o-CoSe2) and cubic CoSe2 (c-CoSe2) by calcining monoclinic Co3Se4 nanotubes (Co3Se4 NTs) prepared by a facile precursor transformation method. Benefiting from advantageous structural features, including functional shells and well-defined interior voids, the tubular-structured o-CoSe2 showed a high power conversion efficiency of 9.34% as a counter electrode catalyst for dye-sensitized solar cells (DSSCs), superior to that of a Pt counter electrode (8.15%), under AM 1.5 G irradiation. In addition, the o-CoSe2 nanotubes also demonstrated excellent electrocatalytic activity in terms of low onset overpotential (∼54 mV) and small Tafel slope (∼65.9 mV per decade) as a hydrogen evolution reaction (HER) catalyst in alkaline medium. Hence, this work provides a promising strategy to selectively design and synthesize highly active electrocatalysts for energy conversion.

This study was mainly aimed at designing molecular p–n heterojunctions on the surface of N-doped TiO2 for visible-light hydrogen evolution. A series of NiO/N-TiO2 samples were prepared via NH3-postnitridation of nickel oxide-modified TiO2. H2 production from ethanol/water solution was utilized as a model reaction to evaluate the photocatalytic properties of the catalysts. Compared to N-TiO2, a 90-fold-enhanced H2 evolution rate was achieved over the optimal NiO/N-TiO2 catalyst with a 0.5 wt% Ni content. Detailed characterizations clearly showed that loading NiO via wet impregnation leads to high dispersion of Ni2+ species on the surface oxygen vacancy (Vo) sites of the anatase TiO2 nanoparticles, predominantly presenting mononuclear Ti–O–Ni heteroatomic clusters on the surface of TiO2 in the case of low Ni content. These surface heteroatomic clusters can speed up the transfer and separation of photogenerated carriers of N-TiO2. It can thus be established that the molecular Ti–O–Ni heterojunctions are the main contributors to the synergistic enhancement of H2 evolution, whereas NiO nanoclusters are not responsible for the photoactivity. Only one of the N species, N–Ti–Vo, was active and effective for this cooperation with the hydrogen-releasing Ni sites, which can induce ca. 20-fold improvement of hydrogen production over NiO/TiO2 under visible light irradiation.

A macroporous SiO2 (Macro-SiO2), which has uniformed macropores, an open-framework structure, and thin walls, was synthesized to support Ziegler–Natta catalysts. The immobilization behaviors of the Ziegler–Natta catalysts inside the Macro-SiO2 were investigated. Notable agglomerations of δ-MgCl2/titanium complex were observed because of the unconstrained environment of the Macro-SiO2. A highly superficial Ti content and a heterogeneously chemical structure of Ti active sites were thus achieved inside the Macro-SiO2. The ethylene polymerization results revealed that the Macro-SiO2/MgCl2/TiCl4 exhibited much higher catalytic activity (i.e., 12.1 × 106 g PE·(mol Ti·h)−1 or 17.8 × kg PE·(g cat·h)−1) than that of the traditional 955-SiO2 supported catalyst (i.e., 2.0 × 106 g PE·(mol Ti·h)−1 or 2.7 × kg PE·(g cat·h)−1). Finally, the fragmentation behavior of Macro-SiO2/MgCl2/TiCl4 was investigated during the polymerization. This unconstrained environment of Macro-SiO2 afforded fewer resistances to the diffusion...

Two novel push–pull type Zn(II) porphyrin dyes ( QX09 and QX10 ) have been synthesized for dye-sensitized solar cells (DSSCs). The two porphyrin dyes consist of the same porphyrin core with a triindole unit directly attached in its meso -position and different acceptor/anchoring groups carboxylic acid (for QX09 ) and cyanoacylic acid (for QX10 ) have been investigated. The photophysical, electrochemical and theoretical studies indicated that the two porphyrin dyes were both suitable as the photosensitizers. The dye QX10 exhibited a broader absorption region and significantly improved IPCE values compared with QX09 , which ensured a better light-harvesting ability and a higher photocurrent. With the coadsorption of chenodeoxycholic acid (CDCA), the DSSCs based on the two dyes both obtained improved photovoltaic performances. Finally, QX10 -based cell with CDCA achieved a high power conversion efficiency of 6.65% under AM 1.5G irradiation.

A new series of organic dyes based on indeno[1,2- b ]indole have been synthesized and applied in dye-sensitized solar cells (DSSCs) for the first time. These four dyes QX11 – 14 are constructed to a D–π–A type structure consisting of an indeno[1,2- b ]indole donor and a cyanoacrylic acid acceptor/anchoring group. Different π-bridges (thiophene and furan) and different alkyl groups (ethyl and hexyl) are involved to tune the photoelectric properties. Their optical, electrochemical, and photovoltaic properties, as well as the density functional theory calculations have been systematically investigated, indicating these four dyes are all capable as photosensitizers. The four dyes all show good DSSC performances and a highest power conversion efficiency up to 7.64% with a J sc of 15.8 mA cm −2 and a V oc of 763 mV has been achieved by the dye QX12 with a furan π-bridge and a pair of ethyl groups, which reaches 95% of the commercial N719 dye (8.07%) under AM 1.5G illumination. This result reveals indeno[1,2- b ]indole is a promising electron donor to construct efficient organic dyes for DSSCs.

Highly efficient and low-cost electrocatalysts are essential for producing hydrogen through water electrolysis. Here ternary compounds CoMoS4 and NiMoS4 were synthesized by a one-step reaction, and further CoMoS4-H and NiMoS4-H were obtained by heating the above two samples under Ar atmosphere. The above four materials both show uniformly small irregular nanoparticles. Each element of the four materials exhibits semblable valence without distinct difference of which S was −2, Mo was +6, Ni and Co were +2. We firstly use the above ternary materials as advanced electrocatalysts for HER over a wide pH range, of which CoMoS4-H displays the best performance with a low onset overpotential at 8 mV in 1.0 M KOH and 83 mV in 0.5 M H2SO4. NiMoS4-H also shows excellent performance with a low onset overpotential at 26 mV in 1.0 M KOH and 160 mV in 0.5 M H2SO4. In 1 M phosphate buffer solution, CoMoS4-H and NiMoS4-H exhibit onset overpotential at overpotential of 122 mV and 152 mV, respectively. These results indicate that the combination of earth-abundant sulfur, cobalt (or nickel) and molybdenum elements can provide highly active electrocatalysts for HER over a wide pH range.