Wuhan University of Technology

About: Wuhan University of Technology is a education organization based out in Wuhan, China. It is known for research contribution in the topics: Microstructure & Catalysis. The organization has 40384 authors who have published 36724 publications receiving 575695 citations. The organization is also known as: WUT.

TiO2/graphene composite photocatalysts for NOx removal: A comparison of surfactant-stabilized graphene and reduced graphene oxide

Abstract: Nanocomposite TiO2/graphene photocatalysts were synthesized via solvothermal process using titanium isopropoxide as a TiO2 precursor. Surfactant-stabilized graphene (ssG) prepared via liquid phase exfoliation and graphene oxide (GO) obtained via oxidation of graphite were used for preparation of two types of composites TiO2/G and TiO2/rGO, respectively, each with graphene loadings 0.01%, 0.1% and 1%. Hydrophilic non ionic surfactant Pluronic F127 was employed in order graphene stabilization in water and homogeneous dispersion with the TiO2 precursor to be achieved. The crystalline structure, composition, morphology, porosity and light absorption of the photocatalysts and their photocatalytic activity in NOx oxidation under UV and visible light irradiation were comparatively investigated. The titania/graphene (ssG and rGO) nanocomposites exhibited higher photocatalytic efficiency than pure TiO2 especially under visible light irradiation in terms of total NOx (NO and NO2) removal and NO2 emission. Differences in the photocatalytic efficiency between the TiO2/G and TiO2/rGO composites were observed originating from the type and the loading of the graphene. In general, the TiO2/rGO exhibited superior efficiency than the TiO2/G and the best results were recorded for low 0.1% graphene loading. The findings are discussed taking into consideration the variation in the BET SSA and the Eg values, as well as the differences in the electronic structure of the ssG and the rGO, the former to be a zero-band gap material and the latter a semiconductor with tunable band gap. The presence of graphene component was determined as a key parameter governing the separation of the photogenerated electron–holes pair through interfacial charge transfer. The significantly increased activity of the TiO2/rGO composites under visible light in NOx removal and the very low levels of NO2 release in comparison to the pure TiO2 render these materials promising photocatalysts for efficient air purification.

A pixel shape index coupled with spectral information for classification of high spatial resolution remotely sensed imagery

Abstract: Shape and spectra are both important features of high spatial resolution remotely sensed (HSRRS) imagery, and they are concrete manifestation of textures on such imagery. This paper presents a spatial feature index, pixel shape index (PSI), to describe the shape feature in a local area surrounding a pixel. PSI is a pixel-based feature which measures the gray similarity distance in every direction. As merely the shape feature is inadequate for classifying HSRRS imagery, a transformed spectral feature extracted by independent component analysis is added to the input vectors of our classifier, and this replaces the original multispectral bands. Meanwhile, a fast fusion algorithm that integrates both shape and spectral features using the support vector machine has been developed to interpret the complex input vectors. The results by PSI are compared with some spatial features extracted using wavelet transform, gray level co-occurrence matrix, and the length-width extraction algorithm to test its effectiveness. The experiments demonstrate that PSI is capable of describing shape features effectively and result in more accurate classifications than other methods. While it is found that spectral and shape features can complement each other and their integration can improve classification accuracy, the transformed spectral components are also found to be more suitable for classification

Magnetoelectric interaction and transport behaviours in magnetic nanocomposite thermoelectric materials

Abstract: How to suppress the performance deterioration of thermoelectric materials in the intrinsic excitation region remains a key challenge. The magnetic transition of permanent magnet nanoparticles from ferromagnetism to paramagnetism provides an effective approach to finding the solution to this challenge. Here, we have designed and prepared magnetic nanocomposite thermoelectric materials consisting of BaFe12O19 nanoparticles and Ba0.3In0.3Co4Sb12 matrix. It was found that the electrical transport behaviours of the nanocomposites are controlled by the magnetic transition of BaFe12O19 nanoparticles from ferromagnetism to paramagnetism. BaFe12O19 nanoparticles trap electrons below the Curie temperature (TC) and release the trapped electrons above the TC, playing an ‘electron repository’ role in maintaining high figure of merit ZT. BaFe12O19 nanoparticles produce two types of magnetoelectric effect—electron spiral motion and magnon-drag thermopower—as well as enhancing phonon scattering. Our work demonstrates that the performance deterioration of thermoelectric materials in the intrinsic excitation region can be suppressed through the magnetic transition of permanent magnet nanoparticles. The ferromagnetic transition in magnetic nanoparticles embedded in magnetic nanocomposite thermoelectric materials is attributed to the trapping and release of electrons, which increases the performance of the thermoelectric materials.

TiO2–MnOx–Pt Hybrid Multiheterojunction Film Photocatalyst with Enhanced Photocatalytic CO2-Reduction Activity

Abstract: Photocatalytic CO2 conversion into solar fuels has an alluring prospect. However, the rapid recombination of photogenerated electron–hole pairs for TiO2-based photocatalyst hinders its wide applica...