Rutile TiO2 mesocrystals/reduced graphene oxide with high-rate and long-term performance for lithium-ion batteries.

An in situ hydrothermal route is developed for fabricating rutile TiO2 mesocrystals/reduced graphene oxide nanosheets (TGR) hybrids in the presence of dodecylbenzenesulphonic acid (ADBS). These rutile TiO2 mesocrystals with a Wulff shape are composed of ultra-tiny rod-like subunits with the same oriented direction and closely wrapped by the nanosheets of reduced graphene oxide (RGO). It is found that ADBS played a key role for the formation of mesocrystals during the self-assembly process, which pillared the graphene oxide (GO) nanosheets and involved the aggregation of the mesocrystal subunits. Furthermore, the TGR hybrids are used as an anode material and exhibited a large capacity over 150 mA h g(-1) at 20 C after 1000 cycles, and high rate capability up to 40 C. These high performance characteristics may be due to the intrinsic characteristics of rutile TiO2 mesocrystals constructed from ultra-tiny subunits and hybridized with super conductive RGO nanosheets.

Separation and purification of furanocoumarins from Toddalia asiatica (L.) Lam. using microwave-assisted extraction coupled with high-speed counter-current chromatography.

A method of microwave-assisted extraction coupled with high-speed counter-current chromatography was established for separation and purification of isopimpinellin, pimpinellin and phellopterin from Toddalia asiatica (L.) Lam. The conditions of MAE including the extraction solvent, size of sample, solid/liquid ratio, extraction temperature and extraction time were optimized by a mono-factor test. That is, 2.0 g dried powder of T. asiatica (L.) Lam of 0.30-0.15 mm size was extracted with 20 mL (solid/liquid ratio of 1:10, g/mL) methanol under 50 °C for 1 min. The crude extract was separated and purified by high-speed counter-current chromatography with hexane-ethyl acetate-methanol-water (5:5:5.5:4.5, v/v/v/v) solvent system. 0.85 mg/g of isopimpinellin, 2.55 mg/g of pimpinellin and 0.95 mg/g of phellopterin were obtained from original sample in one-step within 240 min, the purity determined by high performance liquid chromatography was 95.0%, 99.1% and 96.4%, respectively. Their chemical structures were further identified by mass spectroscopy and nuclear magnetic resonance spectroscopy. The results demonstrated that microwave-assisted extraction coupled with high-speed counter-current chromatography was a feasible, economical and efficient technique for rapid extraction, separation and purification of effective compounds from natural products.