Jian Tian

Ni3S2 nanorods/Ni foam composite electrode with low overpotential for electrocatalytic oxygen evolution

A Ni3S2 nanorods/Ni foam composite electrode is prepared as a high-performance catalyst for the oxygen evolution reaction (OER), which exhibits excellent OER activity with a small overpotential of ∼157 mV based on the onset of catalytic current.

A Bi2WO6‐Based Hybrid Photocatalyst with Broad Spectrum Photocatalytic Properties under UV, Visible, and Near‐Infrared Irradiation

Near-infrared active photocatalytic properties of Bi2 WO6 nanosheets owing to the oxygen vacancies of the Bi2 WO6 nanosheets are reported. The broad spectrum photocatalyst, Bi2 WO6 -TiO2 nanobelt heterostructures, are obtained by assembling Bi2 WO6 nanocrystals on TiO2 nanobelts. The active light band of the novel hybrid photocatalyst with high photocatalytic activity covers full-spectrum solar light including the UV, visible, and near-infrared ranges.

Enhanced photocatalytic performances of CeO2/TiO2 nanobelt heterostructures.

CeO2 /TiO2 nanobelt heterostructures are synthesized via a cost-effective hydrothermal method. The as-prepared nanocomposites consist of CeO2 nanoparticles assembled on the rough surface of TiO2 nanobelts. In comparison with P25 TiO2 colloids, surface-coarsened TiO2 nanobelts, and CeO2 nanoparticles, the CeO2 /TiO2 nanobelt heterostructures exhibit a markedly enhanced photocatalytic activity in the degradation of organic pollutants such as methyl orange (MO) under either UV or visible light irradiation. The enhanced photocatalytic performance is attributed to a novel capture-photodegradation-release mechanism. During the photocatalytic process, MO molecules are captured by CeO2 nanoparticles, degraded by photogenerated free radicals, and then released to the solution. With its high degradation efficiency, broad active light wavelength, and good stability, the CeO2 /TiO2 nanobelt heterostructures represent a new effective photocatalyst that is low-cost, recyclable, and will have wide application in photodegradation of various organic pollutants. The new capture-photodegradation-release mechanism for improved photocatalysis properties is of importance in the rational design and synthesis of new photocatalysts.

Structure, Synthesis, and Applications of TiO2 Nanobelts

TiO2 semiconductor nanobelts have unique structural and functional properties, which lead to great potential in many fields, including photovoltaics, photocatalysis, energy storage, gas sensors, biosensors, and even biomaterials. A review of synthetic methods, properties, surface modification, and applications of TiO2 nanobelts is presented here. The structural features and basic properties of TiO2 nanobelts are systematically discussed, with the many applications of TiO2 nanobelts in the fields of photocatalysis, solar cells, gas sensors, biosensors, and lithium-ion batteries then introduced. Research efforts that aim to overcome the intrinsic drawbacks of TiO2 nanobelts are also highlighted. These efforts are focused on the rational design and modification of TiO2 nanobelts by doping with heteroatoms and/or forming surface heterostructures, to improve their desirable properties. Subsequently, the various types of surface heterostructures obtained by coupling TiO2 nanobelts with metal and metal oxide nanoparticles, chalcogenides, and conducting polymers are described. Further, the charge separation and electron transfer at the interfaces of these heterostructures are also discussed. These properties are related to improved sensitivity and selectivity for specific gases and biomolecules, as well as enhanced UV and visible light photocatalytic properties. The progress in developments of near-infrared-active photocatalysts based on TiO2 nanobelts is also highlighted. Finally, an outline of important directions of future research into the synthesis, modification, and applications of this unique material is given.

Enhanced Photocatalytic Property of Reduced Graphene Oxide/TiO2 Nanobelt Surface Heterostructures Constructed by an In Situ Photochemical Reduction Method

A facile method is proposed to assemble graphene oxide (GO) on the surface of a TiO2 nanobelt followed by an in situ photocatalytic reduction to form reduced graphene oxide (rGO)/TiO2 nanobelt surface heterostructures. The special colloidal properties of GO and TiO2 nanobelt are exploited as well as the photocatalytic properties of TiO2 . Using water-ethanol solvent mixtures, GO nanosheets are tightly wrapped around the surface of the TiO2 nanobelts through an aggregation process and are then reduced in situ under UV-light irradiation to form rGO/TiO2 nanobelt surface heterostructures. The heterostructures enhance the separation of the photoinduced carriers, which results in a higher photocurrent due to the special electronic characteristics of rGO. Compared to TiO2 nanobelts, the rGO/TiO2 nanobelt surface heterostructures possess higher photocatalytic activity for the degradation of methyl orange and for the production of hydrogen from water, as well as excellent recyclability, with no loss of activity over five cycles.

Hydrogenated TiO2 nanobelts as highly efficient photocatalytic organic dye degradation and hydrogen evolution photocatalyst

TiO2 nanobelts have gained increasing interest because of its outstanding properties and promising applications in a wide range of fields. Here we report the facile synthesis of hydrogenated TiO2 (H-TiO2) nanobelts, which exhibit excellent UV and visible photocatalytic decomposing of methyl orange (MO) and water splitting for hydrogen production. The improved photocatalytic property can be attributed to the Ti(3+) ions and oxygen vacancies in TiO2 nanobelts created by hydrogenation. Ti(3+) ions and oxygen vacancies can enhance visible light absorption, promote charge carrier trapping, and hinder the photogenerated electron-hole recombination. This work offers a simple strategy for the fabrication of a wide solar spectrum of active photocatalysts, which possesses significant potential for more efficient photodegradation, photocatalytic water splitting, and enhanced solar cells using sunlight as light source.

UV-visible-light-activated photocatalysts based on Bi2O3/Bi4Ti3O12/TiO2 double-heterostructured TiO2 nanobelts

Surface engineering of TiO2 nanobelts by the controlled assembly of functional heterostructures represents an effective approach for the synthesis of high-performance photocatalysts. In this study, we prepared a novel Bi2O3/Bi4Ti3O12/TiO2 double-heterostructured nanobelt by depositing bismuth hydroxide onto the TiO2 nanobelt surface. A thermal annealing treatment led to the formation of a Bi4Ti3O12 interlayer that functioned as a bridge to link Bi2O3 and TiO2. The double-heterostructured TiO2 nanobelts exhibited better UV light photocatalytic performance than commercial P25. Importantly, the photocatalytic activity in the visible range was markedly better than that of Bi2O3 and Bi2O3/TiO2 heterostructured TiO2 nanobelts. The enhanced performance was accounted for by the material band structures where the matching was improved by the unique interlayer.

Cr(VI), Pb(II), Cd(II) adsorption properties of nanostructured BiOBr microspheres and their application in a continuous filtering removal device for heavy metal ions

Uniform well-defined nanostructured BiOBr microspheres have been fabricated via a simple hydrothermal method in the presence of cetyltrimethylammonium bromide (CTAB) and ethylene glycol (EG). The heavy metal ion adsorption on the as-synthesized nanostructured BiOBr microspheres was systematically assessed by measuring the residual concentration during the adsorption process using a colorimetric method for Cr(VI) concentration, and an extraction-colorimetric method for Cd(II) and Pb(II) concentrations. The nanostructured BiOBr microspheres showed good removal capacity for heavy metal ions (Cr, Cd, Pb), and excellent adsorption properties for low concentration heavy metal ions, indicating potential applications in water purification. Based on the quick and efficient heavy metal ion removal ability of nanostructured BiOBr microspheres, a continuous filtering-type water purification device was designed and constructed. In using this continuous filtering type water purification device, 1 g of adsorbent can purify about 4900 g of Pb(II) contaminated water, 5900 g of Cd(II) contaminated water, or 21 500 g of Cr(VI) contaminated water having initial concentrations of 200 μg L−1 to successfully attain the World Health Organization standard for drinking water. The good removal capacity can be attributed to the hierarchical nanostructure, which displays a large specific surface area and strong adsorption of heavy metal ions.