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Ultrathin semiconductor nanowires are promising alternatives to nanoparticle or bulk counterparts for the construction of photoanodes for solar energy conversion, because of their profuse surface reactive sites and excellent charge transport properties. Herein, well-aligned ultrathin corrugated nanowire TiO2 (UCW-TiO2) thin films with a diameter of 10 nm grown on fluorine-doped tin oxide (FTO) substrates by a unique monomicelle-directed assembly method are applied as a versatile photoanode platform. On this platform, photoanodes were used for direct photoelectrochemical (PEC) benzyl alcohol oxidation and can also be dye-sensitized for visible-light driven water oxidation. The conversion of benzyl alcohol (BA) over the pristine UCW-TiO2 photoanode is close to 100%, and the selectivity can reach 90.2% with a faradaic efficiency of 93% after 15 h. With surface anchoring of a suitable chromophore and oxygen evolution catalysts (OECs), the dye-sensitized UCW-TiO2 photoanode achieves 5-fold larger faradaic efficiency for water oxidation than that of a spherically structured TiO2 assembled photoanode. Electrochemical and spectroscopic measurements demonstrate that the ultrathin corrugated nanowire structured TiO2 accelerates electron transport kinetics and suppresses recombination of surface accumulated holes and electrons compared with spherically structured TiO2. Both BA oxidation and water oxidation studies show that the UCW-TiO2 is a versatile photoanode platform for a variety of highly efficient solar energy conversion applications. [ABSTRACT FROM AUTHOR]

Solar‐to‐hydrogen conversion is a sustainable way of producing renewable fuels, yet the efficiency is limited by the poor photo‐induced charge‐carrier separation on electrode surface. Developing active and stable hydrogen evolution photocatalysts is challenging and entails intelligent material structure design and tailoring. Here, a novel water dispersible supramolecular metal organic framework (SMOF) is employed as a general and high‐performance platform to encapsulate CdS quantum dots (QDs) for achieving highly improved solar‐induced H2‐production activity. Particularly, the CdS QDs@SMOF heterostructure exhibits an excellent H2 generation activity of 49.4 µmol h−1 (TOF = 47.0/h), exceeding those of most reported heterogeneous metal organic frameworks‐based photocatalytic systems. Advanced characterizations disclose that the strong electrostatic interaction and light‐induced charge transfer between SMOF and CdS QDs, combined with the high surface area, water dispersible nature, and abundant reactive centers synergistically contribute to this distinguished photocatalytic performance. The work not only demonstrates the water dispersible SMOF can serve as a versatile and effective platform supporting semiconductor to boost the photocatalytic H2‐production performance without co‐catalysts, but also paves avenues to the design and synthesis of SMOF‐based heterostructures for general catalysis applications. [ABSTRACT FROM AUTHOR]

Herein, a uniform porous highly oriented pyrolytic graphite (HOPG) electrode was prepared via diazonium salt assisted electrochemical etching method and firstly utilized to immobilize enzymes for the construction of a high-performance glucose biosensor. The formation mechanism and morphology structure of the porous HOPG electrode were investigated using atomic force microscopy (AFM), X-ray photoelectron spectroscopy (XPS) and X-ray diffraction (XRD) characterizations. The glucose oxidase (GOx) was functionalized with pyrene groups and then immobilized on the porous HOPG substrate through π-π stacking interactions and hydrogen bonding. As a result, eight times higher oxidation current density can be obtained for a given glucose concentration for the porous HOPG electrode than the pristine one. Detection limit of 5 μM for glucose was achieved for the as-fabricated biosensor. It was obtained that 78 % biocatalytical activity of GOx can be retained after the pyrene functionalization and 65.7 % one can even be maintained after four weeks, which confirmed the high efficiency and good stability of the as-prepared biosensor. What's more, it can be anticipated that various other enzymes can be loaded into this porous HOPG platform using the same enzyme modification methodology for the construction of efficient biosensors. [ABSTRACT FROM AUTHOR]

Herein, a facile and efficient method was developed for fabrication of solid-state electrochemiluminescence (ECL) sensor via non-covalent π-π stacking and covalent bonding on the graphite electrode (GE) surface. The electrode was firstly modified with 1-aminopyrene via π-π stacking between GE surface and the pyrene moiety. Thereafter a stable and efficient solid-state ECL sensor was fabricated by covalent immobilization of ruthenium(II) onto the GE surface via amidation reaction between the 1-aminopyrene and bis(2,2′-bipyridyl)(4-methyl-4′-carboxypropyl-2,2′-bipyridyl) ruthenium(II) bishexafluorophosphate. The sensor has been investigated using tripropylamine and tetracycline as representative analytes, and low detection limits of 0.7 nM and 3.5 nM (S/N=3) were reached, respectively. [ABSTRACT FROM AUTHOR]

The integration of the glycerol oxidation reaction (GOR) with the hydrogen evolution reaction in photoelectrochemical (PEC) cells is a desirable alternative to PEC water splitting since a large quantity of glycerol is easily accessible as the byproduct from the biodiesel industry. However, the PEC valorization of glycerol to the value-added products suffers from low Faradaic efficiency and selectivity, especially in acidic conditions, which is beneficial for hydrogen production. Herein, by loading bismuth vanadate (BVO) with a robust catalyst composed of phenolic ligands (tannic acid) coordinated with Ni and Fe ions (TANF), we demonstrate a modified BVO/TANF photoanode for the GOR with a remarkable Faradaic efficiency of over 94% to value-added molecules in a 0.1 M Na 2 SO 4 /H 2 SO 4 (pH = 2) electrolyte. The BVO/TANF photoanode achieved a high photocurrent of 5.26 mA·cm -2 at 1.23 V versus reversible hydrogen electrode under 100 mW/cm 2 white light irradiation for formic acid production with 85% selectivity, equivalent to 573 mmol/(m 2 ·h). Transient photocurrent and transient photovoltage techniques and electrochemical impedance spectroscopy along with intensity-modulated photocurrent spectroscopy indicated that the TANF catalyst could accelerate hole transfer kinetics and suppress charge recombination. Comprehensive mechanistic investigations reveal that the GOR is initiated by the photogenerated holes of BVO, while the high selectivity to formic acid is attributed to the selective adsorption of primary hydroxyl groups in glycerol on TANF. This study provides a promising avenue for highly efficient and selective formic acid generation from biomass in acid media via PEC cells.

Tungsten oxide (WO 3- x ), a new alternative to conventional semiconductor material, has attracted numerous attentions owning to its widespread potential applications. Various methods have been reported for the synthesis of WO 3- x nanostructures such as nanowires or nanodots. However, templates or surfactants are often required for the synthesis, which significantly complicate the process and hinder the broad applications. Herein, one-pot template/surfactant-free solvothermal method is proposed to synthesize the WO 3- x nanostructures including fluorescent quantum dots (QDs) and bundle-like nanowires simultaneously. The as-prepared WO 3- x QDs can be well dispersed in aqueous medium, exhibit excellent photoluminescent properties, and show an average size of 3.25 ± 0.25 nm as evidenced by transmission electron microscopy. Meanwhile, the diameter of the WO 3- x nanowires is found to be about 27.5 nm as manifested by the scanning electron microscope images. The generation mechanism for these two WO 3- x nanostructures are systematically studied and proposed. The WO 3- x QDs have been successfully applied in efficient fluorescent staining and specific ferric ion detection. Moreover, the WO 3- x nanowires can be utilized as effective dielectric materials for electromagnetic wave absorption., (© 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)