Oxygen Vacancy Engineering of Titania-Induced by Sr2+ Dopants for Visible-Light-Driven Hydrogen Evolution.

A Sr2+-doping strategy is developed to engineer rich oxygen vacancies in porous titania for boosting visible-light-driven photocatalytic activity. The incorporation of strontium, with a larger atom radius than titanium, leads to the release of a lattice oxygen atom in the titania, causing the generation of an oxygen vacancy. The optimal Sr2+-doped titania sample with rich oxygen vacancies achieves a photocatalytic hydrogen production rate as high as 1092 µmol h-1 g-1, which is 4 and 16 times higher than the unmodified titania with less oxygen vacancies and the bench-marked P25, respectively.

[New dammarane type triterpene with cyclization at the side chain from oxidative alkaline-degradation products of PQS].

To study the oxidative alkaline-degradation products of PQS (Panax quinquefolium saponin), two compounds were isolated from the crude product of oxidative alkaline-degradation by silica gel column chromatography, Sephadex LH-20 column chromatography and recrystallized methods. On the basis of spectroscopic analysis, their structures were established as (12R, 20S, 24R)-20, 24; 12, 24-diepoxy-24-deisopropyl-dammarane-3beta-ol (1) and (20S, 24R)-20, 24-epoxydammarane-3beta3, 12beta, 25-triol (2). Compounds 1 and 2, dammarane type triterpene with cyclization at the side chain, were obtained for the first time from alkaline-degradation products of total ginsenosides of Panax quinquefolium L., compound 1 is a new compound.

The influence of structural isomerism on fluorescence and organic dye selective adsorption in two complexes based on flexible ligands.

Based on Cd(NO3)2·4H2O and 4,4'-((5-carboxy-1,3-phenylene)bis(oxy))dibenzoic acid (H3cpbda), two isomeric coordination polymers, {[Cd1.5(cpbda)(bpa)(H2O)2]·1.5H2O}n (1), [Cd(H2cpbda)2(bpa)0.5(H2O)]n (2), were synthesized by using different solvent-systems. The complexes were characterized by single-crystal X-ray diffraction, IR spectroscopy, powder X-ray diffraction, and thermogravimetric analysis. Owing to the obvious structural difference between the two isomeric complexes, the further fluorescence sensing and dye selection and adsorption were investigated. The 3D tight stacking structure of 1 strengthened the fluorescence emission and the loose 2D layer structure of 2 generated the active selection and adsorption of the Malachite Green Oxalate (MGO) dye.