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To circumvent the bottlenecks of non-flexibility, low sensitivity, and narrow workable detection range of conventional biosensors for biological molecule detection (e.g., dopamine (DA) secreted by living cells), a new hybrid flexible electrochemical biosensor has been created by decorating closely packed dendritic Pt nanoparticles (NPs) on freestanding graphene paper. This innovative structural integration of ultrathin graphene paper and uniform 2D arrays of dendritic NPs by tailored wet chemical synthesis has been achieved by a modular strategy through a facile and delicately controlled oil-water interfacial assembly method, whereby the uniform distribution of catalytic dendritic NPs on the graphene paper is maximized. In this way, the performance is improved by several orders of magnitude. The developed hybrid electrode shows a high sensitivity of 2 μA cm−2 μ m−1, up to about 33 times higher than those of conventional sensors, a low detection limit of 5 n m, and a wide linear range of 87 n m to 100 μ m. These combined features enable the ultrasensitive detection of DA released from pheochromocytoma (PC 12) cells. The unique features of this flexible sensor can be attributed to the well-tailored uniform 2D array of dendritic Pt NPs and the modular electrode assembly at the oil-water interface. Its excellent performance holds much promise for the future development of optimized flexible electrochemical sensors for a diverse range of electroactive molecules to better serve society. [ABSTRACT FROM AUTHOR]

We report a facile non-hydrothermal method for the large-scale production of hierarchical TiO2 nanorod spheres for the photocatalytic elimination of contaminants and killing bacteria. Crescent Ti/RF spheres were prepared by deliberately adding titanium trichloride (TiCl3) to the reaction of resorcinol (R) and formaldehyde (F) in an open reactor under heating and stirring. The hierarchical TiO2 nanorod spheres were obtained by calcining the crescent Ti/RF spheres in a furnace in air to burn off the RF spheres. This method has many merits, such as large-scale production, good crystallisation of TiO2, and good reproducibility, all of which are difficult to realise by conventional hydrothermal methods. The calcination temperature plays a significant role in influencing the morphology, crystallisation, porosity, Brunauer-Emmett-Teller (BET) specific surface area, and hierarchy of the TiO2 nanorod spheres, thus resulting in different photocatalytic performances under UV light and solar light irradiation. The experimental results have demonstrated that the hierarchical TiO2 nanorod spheres obtained after calcination of the crescent Ti/RF spheres at different temperatures displayed similar photocatalytic activities under irradiation with UV light. We attribute this to a balance of opposing effects of the investigated factors. A higher calcination temperature leads to greater light absorption capability of the TiO2 nanorod spheres, thus resulting in higher photocatalytic antibacterial activity under solar light irradiation. It is also interesting to note that the hierarchical TiO2 nanorod spheres displayed intrinsic antibacterial activity in the absence of light irradiation, apparently because their sharp outward spikes can easily pierce and penetrate the walls of bacteria. In this study, the sharpest hierarchical TiO2 nanorod spheres were obtained after calcination at 500 °C, and these exhibited the highest antibacterial activity without light irradiation. A higher calcination temperature proved detrimental to the sharpness of the TiO2 nanorods, thus reducing their intrinsic antibacterial activity. [ABSTRACT FROM AUTHOR]

A facile method is designed for the large‐scale production of hierarchical TiO2 nanorod spheres through deliberately adding TiCl3 into the reaction of resorcinol and formaldehyde. After calcination, the resultant TiO2 nanorod spheres exhibit high photocatalytic performances in eliminating contaminants and killing bacteria under UV or solar‐light irradiation. This is of great significance in fabricating well‐crystallized hierarchical TiO2 nanorod spheres for water purification. For more details see the Full Paper by Z. Y. Liu, D. D. Delai et al. on page 3061 ff. [ABSTRACT FROM AUTHOR]