2.3. Evaluation of Photocatalytic Water Splitting 6507 2.3.1. Photocatalytic Activity 6507 2.3.2. Photocatalytic Stability 6507 3. UV-Active Photocatalysts for Water Splitting 6507 3.1. d0 Metal Oxide Photocatalyts 6507 3.1.1. Ti-, Zr-Based Oxides 6507 3.1.2. Nb-, Ta-Based Oxides 6514 3.1.3. W-, Mo-Based Oxides 6517 3.1.4. Other d0 Metal Oxides 6518 3.2. d10 Metal Oxide Photocatalyts 6518 3.3. f0 Metal Oxide Photocatalysts 6518 3.4. Nonoxide Photocatalysts 6518 4. Approaches to Modifying the Electronic Band Structure for Visible-Light Harvesting 6519

Semiconductor-based Photocatalytic Hydrogen Generation

Hydrothermal growth of ZnO nanostructures

To get a real understanding on the complexity of origin and mechanism of visible emission for ZnO quantum dots (QDs), we systematically property of visible emission of ZnO QDs with tunable diameters in a range of 22−78 nm synthesized via a sol−gel route using self-made zinc−oleate complex as a precursor It is indicated that the visible emission of ZnO QDs can be ascribed to singly ionized oxygen vacancies, which is associated with the paramagnetic centers with electron paramagnetic resonance (EPR) value of g = 20056 The visible emission property of the ZnO QDs displays highly size-dependent behavior With ZnO QDs size decreasing, the visible emission peaks blue-shift to the positions with shorter wavelength due to quantum size effect, however, is different from that of band gap Quantitative investigation shows that the visible emission can correspond to a transition of holes from the valence band to the preexisting deep donor energy level, which is different from the well-known conclusion that the v

Origin of Visible Photoluminescence of ZnO Quantum Dots: Defect-Dependent and Size-Dependent

Synthesis of ZnO nanoparticles and study of their antibacterial and antifungal properties

Noble metal/semiconductor nanocomposites play an important role in high efficient photocatalysis Herein, we demonstrate a facile strategy for fabrication of hollow Pt-ZnO nanocomposite microspheres with hierarchical structure under mild solvothermal conditions using Zn (CH3COO)2·2H2O and HPtCl4 as the precursors, and polyethylene glycol-6000 (PEG-6000) and ethylene glycol as the reducing agent and solvent, respectively The as-synthesized ZnO and Pt-ZnO composite nanocrystals were well characterized by powder X-ray diffraction (XRD), nitrogen-physical adsorption, scanning electron microscopy (SEM), energy dispersive X-ray (EDX), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), UV-vis diffuse reflectance spectra (DRS), and photoluminescence (PL) emission spectroscopy It was found that Pt content greatly influences the morphology of Pt-ZnO composite nanocrystals Suitable concentration of HPtCl4 in the reaction solution system can produce well hierarchically hollow Pt-ZnO nanocomposite microspheres, which are composed of an assembly of fine Pt-ZnO nanocrystals Photocatalytic tests of the Pt-ZnO microspheres for the degradation of the dye acid orange II revealed extremely high photocatalytic activity and stability compared with those of pure ZnO and corresponding Pt deposited ZnO The remarkable photocatalytic performance of hollow Pt-ZnO microspheres mainly originated from their unique nanostructures and the low recombination rate of the e−/h+ pairs by the platinum nanoparticles embedded in ZnO nanocrystals

Novel hollow Pt-ZnO nanocomposite microspheres with hierarchical structure and enhanced photocatalytic activity and stability

Well-aligned single-crystalline ZnO nanobelt arrays were fabricated on a Si wafer by a carbothermal reduction route with the assistance of a SnO2/Sn species. The as-prepared ZnO nanobelt arrays were characterized by X-ray diffraction, scanning electron microscopy, energy dispersive X-ray spectroscopy, transmission electron microscopy, UV−vis spectroscopy, and photoluminescence spectroscopy. The photocatalytic activity for methyl orange on the ZnO nanobelt arrays was also investigated under UV irradiation. The ZnO nanobelts are several tens of nanometers in thickness, 100−500 nm in width, and have a length of up to several micrometers. It has been found that the ZnO nanobelt arrays form on a substrate only when the thickness of the SnO2 coating is less than 100 nm. The rod-/comb-like ZnO nanostructures and the ZnO film can be obtained by increasing the SnO2 loading or the temperature, respectively. The ZnO nanobelts grow from the active surface at the nanobelt root via a vapor−liquid−solid mechanism. The Z...

Tianjun Sun

Papers

Controllable Fabrication and Photocatalytic Activity of ZnO Nanobelt Arrays