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• Charge storage performance of functionalized porphyrin complexes is regulated by electron-donating/withdrawing groups. • Strong electron withdrawing effect of chlorine functionalized groups enables higher reversible capacity. • Extremely cycling stability up to 2000 cycles with capacity retention more than 80% is achieved. • Multiple electrons transfer mechanism in porphyrin electrode is evidenced. Organic electrode materials exhibit wide application prospects in the electrochemical energy storage devices, owing to their adjustable structure, low cost and environmental friendliness. Though organic electrode materials delivered high theoretical energy density, but suffer from low electronic conductivity and high solubility. In order to decrease the solubility and regulate redox potential of the porphyrin molecule, electron-donating group and electron-withdrawing group were functionalized on bipolar porphyrin complex. Herein, we report two novel cathodes of [5,15-bis(ethynyl)-10,20-bis(5-methylthienyl) porphinato] copper(II) (CuDETMP) and [5,15-bis(ethynyl)-10,20-bis(5-chlorothienyl)porphinato]copper(II) (CuDETCP). Strong electron withdrawing effect of chlorine functionalized groups enables higher reversible capacity (≈125 mAh/g vs 100 mAh/g at 1 A/g), while with electron donating group of CuDETMP showed stable cycling capability. Extremely cycling stability up to 2000 cycles with capacity retention more than 80% was achieved in both electrodes. Compared to CuDETMP, higher capacity of CuDETCP benefits from reaction between chlorine atoms and Li cations, which can be a partially reversible process lead to degraded capacity. Nevertheless, CuDETMP and CuDETCP can deliver reversible capacity and provide multiple-redox sites enabling high energy density in respective proper voltage ranges. Through comparison towards physical and electrochemical properties of two molecules, mechanism between substituent and electrochemical performance was clarified. This work not only elaborates the significant correlation between different substituents and electrochemical performance, but also provides a novel strategy to tunable molecular design of organic electrode materials for high-energy rechargeable organic lithium batteries. [ABSTRACT FROM AUTHOR]

Abstract A kind of silicone rubber (SR)/paraffin (Pa)@silicon dioxide (SiO 2) composite form-stable phase change material (PCM) was developed in this paper. Pa@SiO 2 was obtained by choosing Pa as PCM core microencapsulated in SiO 2 shell based on tetraethoxysilane (TEOS) and γ-aminopropyl triethoxysilane (APTES) as precursors, then Pa@SiO 2 microencapsules were embedded in SR matrix to fabricate SR/Pa@SiO 2 composites. The SiO 2 shell can provide a barrier for the melted Pa and meanwhile have reinforcing effect on SR as inorganic filler. The in-situ modification of SiO 2 shell using APTES owing to the amino groups can not only prevent agglomeration, but also increase interfacial bonding between Pa@SiO 2 with SR. The thermal and mechanical properties of the form-stable PCMs were characterized by differential scanning calorimetry (DSC) and mechanical tests. The results showed that the thermal and mechanical properties of SR/Pa@SiO 2 composites were better than those of SR/Pa and SR/Pa/SiO 2. Leakage test was conducted by heating the prepared composites over the melting temperature of Pa. The SR/Pa@SiO 2 composites were found as form-stable PCM with low leakage rate. The phase change latent heat of the SR/Pa@SiO 2 composites was up to 92.39 J g−1 and the composites can be used for thermal energy storage. Highlights • Developed a novel and efficient process for amino terminated paraffin (Pa)@SiO 2 microencapsules. • The Pa@SiO 2 microencapsules were embedded in silicone rubber (SR) matrix to fabricate SR/Pa@SiO 2 composites. • The SiO 2 shell can provide a barrier for the melted Pa and meanwhile have reinforcing effect on SR as inorganic filler. • The phase change latent heat of the SR/Pa@SiO 2 composites was up to 92.39 J g−1. [ABSTRACT FROM AUTHOR]

Abstract A series of paraffin/expanded graphite (EG) composites with various mass fraction were prepared. The microscopic geometry configuration, thermal conductivity and saturation sorption capacity of EG were obtained. In this paper, a method based on the experiments of EG pores was proposed for constructing geometric models. The geometric model constructed by this method has obvious anisotropy and has been employed in the calculation. Furthermore, the numerical results of thermal conductivity indicate anisotropy of a single-pore. Moreover, it had been observed by experiment that the anisotropy is weakened and transformed to isotropy in the process of combining geometric models with a large number of single pores. The final numerical results agree well with the experiments, which validates the precision and reliability of the proposed model. The increasement of thermal conductivity is also calculated and discussed during the phase change process of paraffin/EG. Highlights • A method of EG pores was proposed for constructing geometric models which has obvious anisotropy. • The SEM micrograph and saturation sorption capacity are employed to build the geometric models of EG pores. • Effective thermal conductivity during non-phase change process and the phase change process was calculated. • The numerical results agree well with the experiments. [ABSTRACT FROM AUTHOR]

Abstract Composite of g-C 3 N 4 and poly(3-hexylthiophene) (P3HT) with enhanced photocatalytic H 2 production activity was prepared by polymerizing 3-hexylthiophene and g-C 3 N 4 , which was treated with thiophene-3-acetic acid (T3A). The morphology, chemical structure, and light absorption properties of samples were characterized by SEM, TEM, BET, XRD, FT-IR, XPS, UV–visible diffuse reflectance spectra (UV–vis). The migration and separation efficiency of charge carriers were characterized by photoluminescence (PL) emission spectra, Time resolved photoluminescence spectra, transient photocurrent responses, and electrochemical impedance spectroscopy (EIS). The photocatalytic activity of the catalysts were tested as the H 2 evolution rate from water under visible light irradiation in the presence of triethanolamine as sacrifice agent. The results indicated that g-C 3 N 4 -P3HT composite shows significant enhanced migration and separation efficiency of charge carriers, and photocatalytic H 2 production activity from water. The intrinsic nature causing the significance enhanced photocatalytic performance was discussed. Our findings here may provide a new strategy to design composite photocatalyst with high photocatalytic activity. Graphical abstract Image 1 Highlights • Composite of g-C 3 N 4 and P3HT was prepared by polymerizing T3A treated g-C 3 N 4 and 3HT. • The composite shows higher charge carriers migration and separation efficiency than g-C 3 N 4. • The photocatalytic activity of the composite was 12 times of that of g-C 3 N 4. [ABSTRACT FROM AUTHOR]

Paraffin, due to its linear chain and saturated hydrocarbons with low thermal conductivity, is difficult to transfer energy effectively. Using amphiphilicity of graphene oxide (GO), Pickering emulsion of paraffin@GO was obtained and then paraffin@graphene microencapsulated phase change materials (MEPCMs) were achieved by chemical reduction through adding hydrazine hydrate. Thermally conductive PCMs with segregated structure were constructed by hot compression of paraffin@graphene microencapsules. Scanning electronic microscopy, differential scanning calorimetry and thermal conductivity test were used to characterize microstructure and thermal properties of MEPCMs. Meanwhile, the effect of graphene on the phase change latent heat and phase transition temperature was investigated. Results indicated that GO did not react with paraffin during the process of chemical reduction and the obtained MEPCMs were regular spheres. These MEPCMs had paraffin content of 99% or even more. Graphene working as shell materials increased the phase change latent heat of paraffin from 227.6 to 232.4 J/g, without affecting the phase transition temperature. The hot-compress molding makes graphene shell form segregated structure with more thermal pathways, further enhancing thermal conductivity. The segregated-structure PCMs with high latent heat and thermal conductivity can be applied in energy storage field. [ABSTRACT FROM AUTHOR]

[Display omitted] • Thiophene functionalized porphyrin is proposed as new cathode for organic-sodium batteries. • In-situ polymerization strategy renders excellent cycling stability (11000 cycles). • High energy (508 Wh kg−1) and power density (18 KW kg−1) are achieved as well. • Nitrogen and Sulfur atoms are active sites for charge storage. Organic-sodium batteries have attracted extensive attention due to the abundance of sodium resource and the molecular tunability of organic materials. However, the dissolution of organic materials in electrolytes and low electronic conductivity limit its development. Here, a porphyrin complex of [5,15-di(thiophen-2-yl) porphinato] M(II) (MTP, M = Cu, Ni) is proposed as highly stable cathode material for organic-sodium batteries. Benefiting from the multiple electron transfer of metal porphyrin complex and in-situ polymerization of thiophene groups of porphyrin complex in initial cycles, the CuTP cathode delivers a reversible capacity of 203 mAh/g at 100 mA g−1 and long-term cycling stability up to 11,000 cycles at a high current density of 5 A/g owing to the enhanced conjugated structure induced by in situ polymerization process. A specific energy density of 508 Wh kg−1 and a power density of 18 KW kg−1 are achieved for metal porphyrin-based cathode. The charge storage sites and in-situ polymerization mechanism of MTP cathode are systematically evaluated by both experimental and simulated studies. This study would provide a new strategy to address the dissolution issue of organic cathode and improve cycling stability of the organic-sodium batteries. [ABSTRACT FROM AUTHOR]

Novel microencapsulated phase change materials (MEPCMs) with high encapsulation capacity and enhanced leakage-prevention performance were prepared by in situ polymerization. For these MEPCMs, paraffin and melamine-formaldehyde resin (MF) are respectively used as core and shell, and graphene oxide (GO) nanosheets, which can be seen as extra protective screen, are situated at the interface between the core and the shell. Effects of GO on morphology, microstructure and properties of MEPCMs were characterized by scanning electronic microscopy (SEM), laser diffraction particle analyzer, atomic force microscopy (AFM), Fourier transformation infrared spectroscopy (FTIR), X-ray diffractometry (XRD), transmission electron microscopy (TEM), differential scanning calorimetry (DSC), thermogravimetric analysis (TG) and paraffin leakage rate test. The results show that the fabricated MEPCMs with GO nanosheets have gradual increasing average diameters from 6.32 to 15.89 μm with an increase content of GO, while the size of MEPCMs without GO is 5.63 μm. When the time of leakage rate test is 50 h, the MEPCMs prepared with 0.5 mg/mL GO aqueous dispersion have considerably high encapsulation ratio of 93.9 wt.%, and the leakage rate is reduced by 93.1% compared with those without GO. The high encapsulation capacity and enhanced leakage-prevention performance might be highly attractive for the application of MEPCMs. [ABSTRACT FROM AUTHOR]

new surface ion-imprinted composite polymer containing 3-methyl-1-phenyl −4-(cis-acylbutenoic acid)-2-pyrazolin-5-one as the functional reagent is presented that is capable of extracting and preconcentrating traces of Th(IV) ion prior to its photometric determination. Parameters affecting the recovery of Th(IV) such as acidity, shaking time, initial concentration of Th(IV), elution condition, sample flow rate, and influence of potentially interfering ions were investigated. The maximum uptake capacity of this material and that of the non-imprinted polymer at pH 4.5 are 56.8 and 26.3 mg g, respectively. Recovery exceeds 95% and is complete within 5 min. A Langmuir isotherm fits the experimental data. The relative selectivity factor for Th(IV)/U(VI), Th(IV)/La(III), and Th(IV)/Ce(III) are 50.8, 78.3, and 82.6, respectively. The relative standard deviation is <2.5%, the detection limit is 0.54 μg L (3σ). The imprinted polymer was coupled to spectrophotometry to separate and determine trace levels of Th(IV) in a soil standard material with satisfactory results. [Figure not available: see fulltext.] [ABSTRACT FROM AUTHOR]