High Pressure Rapid Synthesis of LiCrTiO4 with Oxygen Vacancy for High Rate Lithium-Ion Battery Anodes.

Lithium-ion battery based on LiCrTiO4 (LCTO) is considered to be a promising anode material, as they provide higher safety and durability beyond than that of graphite electrode. However, the applications of this transformative technology demand improved inherent electrical conductivity of LCTO as well as a simple and rapid synthetic route. Here, LCTO with oxygen vacancies (OVs) is fabricated using high-pressure synthesis technology in only 40 min. The optimal synthesis pressure is 0.8 GPa (LCTO-0.8). The reversible capacity of LCTO-0.8 at 1C is 131 mA h g-1 after 1000 cycles and the capacity retention is nearly 97%, and the reversible capacity of LCTO synthesized at atmospheric pressure (LCTO-P) is 85 mA h g-1 under the same circumstances. Even at 5C, the reversible capacity is 110 mA h g-1 , which is 77% higher than LCTO-P. Furthermore, it is confirmed by theoretical calculations that the introduction of OVs has the occupation of electronic states at the Fermi level, which greatly enhances the intrinsic conductivity of LCTO. Specifically, the electronic conductivity has increased by two orders of magnitude compared with LCTO-P. Therefore, high-pressure synthesis technology endows LCTO with superior characteristics, providing a new avenue for industrialization.

Effect of Pb Filling and Synthesis Pressure Regulation on the Thermoelectric Properties of CoSb3.

To take the advantage of the synergy of atom filling and pressure regulation, atom Pb was assumed to play the role of fillers to occupy the Sb-icosahedron voids. In this paper, skutterudite Pb xCo4Sb11.5Te0.5 materials have been synthesized by high-pressure and high-temperature (HPHT) method with 0.5 h processing time. Although the increase of Pb filling rate increased the electrical resistivity of samples, it reduced the thermal conductivity of samples significantly. When the synthesis pressure increased, the Seebeck coefficients of Pb0.2Co4Sb11.5Te0.5 increased, and the thermal conductivity decreased. The crystal morphology and structure of samples, which can effectively affect the thermoelectric properties of materials, were investigated with XRD, Raman spectra, SEM mapping, and HR-TEM analysis.

Enhanced Thermoelectric Properties of Double-Filled CoSb3 via High-Pressure Regulating.

It has been discussed for a long time that synthetic pressure can effectively optimize thermoelectric properties. The beneficial effect of synthesis pressures on thermoelectric properties has been discussed for a long time. In this paper, it is theoretically and experimentally demonstrated that appropriate synthesis pressures can increase the figure of merit (ZT) through optimizing thermal transport and electronic transport properties. Indium and barium atoms double-filled CoSb3 samples were prepared use high-pressure and high-temperature technique for half an hour. X-ray diffraction and some structure analysis were used to reveal the relationship between microstructures and thermoelectric properties. In0.15Ba0.35Co4Sb12 samples were synthesized by different pressures; sample synthesized by 3 GPa has the best electrical transport properties, and sample synthesized by 2.5 GPa has the lowest thermal conductivity. The maximum ZT value of sample synthesized by 3.0 GPa reached 1.18.

Planar tetracoordinate carbon species CLi3E with 12-valence-electrons.

We exhibit theoretically a series of 12-valence-electron pentaatomic species CLi3E (E = N, P, As, Sb, Bi) and CLi3E(+) (E = O, S, Se, Te, Po). The analyses of potential energy surfaces indicate that the C2v structures with a planar tetracoordinate carbon are the global minimum in these species except for E = N, P. A localized C[double bond, length as m-dash]E double bond is found in the planar tetracoordinate carbon species. The molecular orbitals and the valence populations reveal that the C[double bond, length as m-dash]E double bonds in CLi3E are different from those in CLi3E(+). The thermodynamic and kinetic calculations show that some of the planar tetracoordinate carbon species are stable and are likely to exist in the gas phase.

Unconventional charge distribution in the planar wheel-type M©B6H6(-/0/+) (M = Mn, Fe and Co): central M with negative charges and peripheral boron ring with positive charges.

Planar wheel-type D6h M©B6H6(-/0/+) (M = Mn, Fe and Co for anion, neutral and cation, respectively.) clusters with a planar hexacoordinate transition-metal at the center of the boron ring were designed and investigated by density functional theory. These planar clusters are chemically stable as a result of their large binding energy, vertical ionization potential, and vertical electron affinity. The detailed natural population and molecular orbital analyses suggest that not only does the M atom donate electrons to the boron ring for participation in the π-delocalized bonding, but also the boron ring donates electrons back to the M atom for the formation of the σ-delocalized bonding, which leads to a strong aromaticity and unconventional charge distribution, i.e., the M atom is negatively charged, while the boron ring is positively charged. This study may open a new area in coordination chemistry for planar hexacoordinate transition metals and we expect further experimental exploration of their synthesis and potential applications.

Enhanced non-linear optical properties of porphyrin-based polymers covalently functionalized with graphite phase carbon nitride.

In our work, a flurry of original porphyrin-based polymers covalently functionalized g-C3N4 nanohybrids were constructed and nominated as PPorx-g-C3N4 (x = 1, 2 and 3) through click chemistry between porphyrin-based polymers with alkyne end-groups [(PPorx-C≡CH (x = 1, 2 and 3)] and azide-functionalized graphitic carbon nitride (g-C3N4-N3). Due to the photoinduced electron transfer (PET) between porphyrin-based polymers [PPorx (x = 1, 2 and 3)] group and graphite phase carbon nitride (g-C3N4) group in PPorx-g-C3N4 nanohybrids, the PPorx-g-C3N4 nanohybrids exhibited better non-linear optical (NLO) performance than the corresponding PPorx-C≡CH and g-C3N4-N3. It found that the imaginary third-order susceptibility (Im [χ(3)]) value of the nanohybrids with different molecular weight (MW) of the pPorx group in the nanohybrids ranged from 2.5×103 to 7.0 × 103 g mol-1 was disparate. Quite interestingly, the Im [χ(3)] value of the nanohybrid with a pPorx group's MW of 4.2 × 103 g mol-1 (PPor2-g-C3N4) was 1.47 × 10-10 esu, which exhibited the best NLO performance in methyl methacrylate (MMA) of all nanohybrids. The PPorx-g-C3N4 was dispersed in polymethyl methacrylate (PMMA) to prepare the composites PPorx-g-C3N4/PMMA since PMMA was widely used as an alternative to glass. PPor2-g-C3N4/PMMA showed the excellent NLO performance of all nanohybrids with the Im [χ(3)] value of 2.36 × 10-10 esu, limiting threshold of 1.71 J/cm2, minimum transmittance of 8% and dynamic range of 1.09 in PMMA, respectively. It suggested that PPorx-g-C3N4 nanohybrids were potential outstanding NLO materials.

Effects of exogenous 6-BA and NAA on growth and contents of medicinal ingredient of Phellodendron chinense seedlings.

Using Phellodendron chinense seedlings as material, and treated with different concentrations of exogenous 6-Benzylaminopurine (6-BA) and α-naphthyacetic acid (NAA), then observed the growth status. Furthermore, we detected the contents of chlorophyll and soluble sugar, the activities of antioxidases by spectrophotometry, and determined the contents of secondary metabolite by high performance liquid chromatograph. The results showed that different concentrations of exogenous 6-BA increases the fresh weights and plant heights of Phellodendron chinense seedlings, and enhances the contents of chlorophyll and soluble sugar. NAA promoted growth, but deduced the contents of soluble sugar. Compared with control, culturing for 40 d, proper concentrations 6-BA enhanced the activity levels of superoxide dismutase (SOD), peroxidase (POD) and catalase (CAT), proper concentrations NAA increased the activity levels of SOD and CAT, but decreased the levels of POD compared with CK. Suitable concentrations 6-BA enhanced contents of berberine, phellodendrine and palmatine in stems, proper concentrations NAA increased contents of berberine and phellodendrine, but deduced contents of palmatine compared with CK. Based on these results, we concluded that the exogenous 6-BA and NAA had key regulation on the growth and contents of medicinal ingredient of Phellodendron chinense seedlings.

High-efficient extraction of principal medicinal components from fresh Phellodendron bark (cortex phellodendri).

There are three key medicinal components (phellodendrine, berberine and palmatine) in the extracts of Phellodendron bark, as one of the fundamental herbs of traditional Chinese medicine. Different extraction methods and solvent combinations were investigated to obtain the optimal technologies for high-efficient extraction of these medicinal components. RESULTS: The results showed that combined solvents have higher extracting effect of phellodendrine, berberine and palmatine than single solvent, and the effect of ultrasonic extraction is distinctly better than those of distillation and soxhlet extraction. CONCLUSION: The hydrochloric acid/methanol-ultrasonic extraction has the best effect for three medicinal components of fresh Phellodendron bark, providing an extraction yield of 103.12 mg/g berberine, 24.41 mg/g phellodendrine, 1.25 mg/g palmatine.

Graphene oxide caged in cellulose microbeads for removal of malachite green dye from aqueous solution.

A simple sol-gel method using non-toxic and cost-effective precursors has been developed to prepare graphene oxide (GO)/cellulose bead (GOCB) composites for removal of dye pollutants. Taking advantage of the combined benefits of GO and cellulose, the prepared GOCB composites exhibit excellent removal efficiency towards malachite green (>96%) and can be reused for over 5 times through simple filtration method. The high-decontamination performance of the GOCB system is strongly dependent on encapsulation amount of GO, temperature and pH value. In addition, the adsorption behavior of this new adsorbent fits well with the Langmuir isotherm and pseudo-second-order kinetic model.

Performance enhancement of ZnO UV photodetectors by surface plasmons.

Surface plasmons, a unique property of metal nanoparticles, have been widely applied to enhance the performance of optical and electrical devices. In this study, a high quality zinc oxide (ZnO) thin film was grown on a quartz substrate by a radio frequency magnetron sputtering technique, and a metal-semiconductor-metal structured ultraviolet detector was prepared on the ZnO film. The responsivity of the photodetector was enhanced from 0.836 to 1.306 A/W by sputtering metal (Pt) nanoparticles on the surface of the device. In addition, the absorption of the ZnO thin film was enhanced partly in the ultraviolet band. It is revealed that Pt nanoparticles play a key role in enhancing the performance of the photodetectors, where surface plasma resonance occurs.