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Abstract: A novel hierarchical titanium dioxide (TiO2) composite nanostructure with strings of anatase TiO2 hierarchical micro-spheres and rutile nanobelts framework (TiO2 HSN) is successfully synthesized via a one-step hydrothermal method. Particularly, the strings of hierarchical spheres are assembled by very thin TiO2 nanosheets, which are composed of highly crystallized anatase nanocrystals. Meanwhile, the HSN has a large surface area of 191m2/g, which is about 3 times larger than Degussa P25. More importantly, the photocatalytic activity of HSN and P25 were evaluated by the photocatalytic oxidation decomposition of methyl orange (MO) under UV light illumination, and the TiO2 HSN shows enhanced photocatalytic activity compared with Degussa P25, as result of its continuous hierarchical structures, special conductive channel and large specific surface area. With these features, the hierarchical TiO2 may have more potential applications in the fields of dye-sensitized solar cells and lithium ion batteries. [Copyright &y& Elsevier]

Abstract: Titanium dioxide (TiO2) nanoflower clusters (NFC) composed of anatase TiO2 nanoflowers and TiO2 nanobelts framework were prepared through a simple hydrothermal synthesis. Then a novel nanocomposite photoanode were fabricated by mixing NFC and P25 nanoparticles in different mass ratio. The highest conversion efficiency of 6.38% (16% higher than P25 based DSSC) is achieved for dye-sensitized solar cells (DSSCs) made by a 5:5 (wt/wt) mixture of NFC and P25. The higher efficiency using mixed photoanode derives from the high light harvesting and good transferring properties of NFC, as well as the sufficient dye absorption due to the high specific surface area of P25 nanoparticles. [Copyright &y& Elsevier]

Anatase titanium dioxide (TiO) nanoflowers were fabricated on rutile TiO nanobelts through a simple hydrothermal synthesis. The architecture of the composite nanostructures was composed of a rutile nanobelt framework with anatase nanoflowers. The novel TiO composite nanostructures exhibit higher photocatalytic activity for organic pollutants relative to TiO nanobelts and commercially available nanoparticles (P25). This enhanced photocatalytic activity is primarily a result of complex crystal nanostructures that enhance the carrier transport along the nanobelt framework. The results indicate that this novel TiO nanostructure has superior photocatalytic properties, which demonstrates its potential as a new photocatalyst material. [ABSTRACT FROM AUTHOR]

Effective photolytic regeneration of the NAD(P)H cofactor in enzymatic reductions is an important and elusive goal in biocatalysis. It can, in principle, be achieved using a near-infrared light (NIR) driven artificial photosynthesis system employing H 2 O as the sacrificial reductant. To this end we utilized TiO 2 /reduced graphene quantum dots (r-GQDs), combined with a novel rhodium electron mediator, to continuously supply NADPH in situ for aldo-keto reductase (AKR) mediated asymmetric reductions under NIR irradiation. This upconversion system, in which the Ti-O-C bonds formed between r-GQDs and TiO 2 enabled efficient interfacial charge transfer, was able to regenerate NADPH efficiently in 64 % yield in 105 min. Based on this, the pharmaceutical intermediate (R)-1-(3,5-bis(trifluoromethyl)phenyl)ethan-1-ol was obtained, in 84 % yield and 99.98 % ee, by reduction of the corresponding ketone. The photo-enzymatic system is recyclable with a polymeric electron mediator, which maintained 66 % of its original catalytic efficiency and excellent enantioselectivity (99.9 % ee) after 6 cycles. [Display omitted] [ABSTRACT FROM AUTHOR]

Titanium dioxide (TiO 2 ) based dye-sensitized solar cells (DSSCs) often exhibit superior power conversion performance. Here we report a DSSC with novel hierarchical TiO 2 composite structure (TCS) composed of anatase TiO 2 micro-spheres and rutile TiO 2 nanobelt framework by hydrothermal approach for high-performance. As photoanode, the TCS based DSSC shows a strong efficiency enhancement by 58% compared with Degussa TiO 2 (P25)-DSSC (4.33%). The excellent performance is mainly attribute to its special multi-dimensional structures of TiO 2 : much active sites of 0D nanoparticle with exposed excellent {001} facet, special electronic transmission channel of 1D nanobelt, good dye adsorption capacity of 2D nanosheet and high light scattering ability of 3D micro-spheres. The novel multi-dimensional TCS materials will open up a new avenue to the electronic devices fields. [ABSTRACT FROM AUTHOR]