Showing papers by "Xiaobo Chen published in 2014"
TL;DR: Generations Yi Ma,† Xiuli Wang,† Yushuai Jia,† Xiaobo Chen,‡ Hongxian Han,*,† and Can Li*,†
Abstract: Generations Yi Ma,† Xiuli Wang,† Yushuai Jia,† Xiaobo Chen,‡ Hongxian Han,*,† and Can Li*,† †State Key Laboratory of Catalysis, Dalian Institute of Chemical Physics, Chinese Academy of Sciences and Dalian National Laboratory for Clean Energy, 457 Zhongshan Road, Dalian 116023, China ‡Department of Chemistry, College of Arts and Sciences, University of Missouri-Kansas City, 5100 Rockhill Road, Kansas City, Missouri 64110, United States
1,990 citations
420 citations
342 citations
TL;DR: In this paper, a 10-time lithium rate improvement and 4-time photocatalytic performance enhancement have been achieved with TiO 2 nanocrystals when coated with a thin layer of amorphous carbon.
172 citations
TL;DR: In this article, a series of nanostructured TiO2-CdS composite photocatalysts have been synthesized using an aqueous solution route at room temperature, and characterized with X-ray diffraction (XRD), Raman spectroscopy, transmission electron microscopy (TEM), UV-VIS absorption and Fourier transform infrared spectrography (FTIR).
158 citations
TL;DR: In this article, the authors investigated vacuum-treated TiO2 nanocrystals and found that they displayed long-wavelength optical absorption due to the existence of oxygen vacancy and Ti3+ defects, and possibly the surface structural disorder.
150 citations
TL;DR: In this article, the authors showed that hydrogenation is a powerful tool to enhance the optical and photocatalytic performance of nanomaterials, and they further demonstrated that hydrogenated black ZnO nanoparticles display long-wavelength absorption and excellent photocatalysis performance.
Abstract: Following our previous findings on hydrogenated black TiO2 nanoparticles, here, we would like to present our exciting findings on hydrogenated black ZnO nanoparticles, which have displayed long-wavelength absorption and excellent photocatalytic performance. This further demonstrates that hydrogenation is a powerful tool to enhance the optical and photocatalytic performance of nanomaterials.
75 citations
TL;DR: In this paper, the authors proposed a collective-movement-of-interfacial-dipole (CMID) mechanism to solve the problem of poor microwave absorption of TiO2 nanoparticles.
Abstract: TiO2 has attracted tremendous research interest for photocatalytic water splitting, solar hydrogen generation, environmental pollution removal, dye-sensitized solar cells, lithium-ion batteries, supercapacitors, and field emission. Microwave absorption materials (MAMs) play important roles in many military (e.g., the stealth coating on the B-2 bomber) and civil (e.g., telecommunications, noise reduction, information security, signal, and data protection) applications. However, TiO2 is not a good MAM due to its poor absorption in the microwave region. Here, we report that via hydrogenation excellent and tunable microwave absorption is achieved with hydrogenated TiO2 nanocrystals. After hydrogenation, 4.3x and 103x improvements have been obtained in storing and dissipating the electric energy of the microwave electromagnetic field. Their permittivity values are higher than those of the current carbonaceous MAMs. Instead of relying on the dipole rotation or ferromagnetic resonance mechanisms for traditional MAMs, the hydrogenated TiO2 nanocrystals work as good MAMs based on a newly proposed collective-movement-of-interfacial-dipole (CMID) mechanism. Although there is still no direct physical evidence of the interface effects of the CMID mechanism, the CMID as a hypothesis at this point successfully explained the origin of the enhanced microwave absorption of the hydrogenated TiO2 nanoparticles. This study thus may open new applications for TiO2 nanocrystals and also stimulate new approaches for new MAM development.
74 citations
TL;DR: In this article, the authors found that small TiO2 nanoparticles were formed at the very beginning stage of the reaction, then were transformed into large TiOF2 crystals, and finally turned into (001)-faceted nanosheets.
Abstract: The rapid depletion of the fossil fuel reserves, and the increase of green-house gas emissions and other environmental pollutants, bring up an urgent need for the development of clean energy and sustainable environmental solutions. The ability to use sunlight to produce fuels such as H2 from abundant, non-toxic resources, and to decompose environmental pollutants with benign photocatalysts, would revolutionize our civilization. TiO2 has attracted substantial interest due to its activity for generating hydrogen from water under ultraviolet (UV) light irradiation. The discovery of (001) facet control with the fluoride additive in the reactants has triggered intensive studies for model photocatalysis. Here, we found that small TiO2 nanoparticles were formed at the very beginning stage of the reaction, then were transformed into large TiOF2 crystals, and finally turned into (001)-faceted TiO2 nanosheets. TiOF2 acted as a metastable intermediate medium in the transformation from TiO2 nanoparticles into (001)-faceted TiO2 nanosheets. The (001) face showed higher activity for the photocatalytic generation of hydrogen and the photodecomposition of methylene blue and rhodamine B. The synergic effect between TiOF2 and TiO2 nanosheets or nanoparticles further improved the photocatalytic activities. This study provides us with a promising solution for solving the energy and environment problems.
31 citations
TL;DR: In this paper, the photocatalytic hydrogen generation from pure (deionized) water under simulated solar light with silicon carbide (SiC) nanoparticles, without the assistance of sacrificial reagents or precious metal co-catalysts, was reported.
Abstract: We report here the photocatalytic hydrogen generation from pure (deionized) water under simulated solar light with silicon carbide (SiC) nanoparticles, without the assistance of sacrificial reagents or precious metal co-catalysts. We have studied the pH effects of the addition of methanol and the loading of a Pt co-catalyst on the photocatalytic hydrogen generation efficiency of SiC nanoparticles. We have found that SiC nanoparticles display the best photocatalytic hydrogen generation efficiency in pure water. SiC nanoparticles show activity in both ultraviolet (UV) and visible-light regions. The addition of methanol in water or loading of Pt nanoparticles on the surface lowers their activity. Thus, SiC nanoparticles may serve as an ideal model photocatalyst for future studies in generating hydrogen from pure water.
30 citations
TL;DR: In this paper, the influence of surface morphology on the lithium-ion battery performance of TiO2, a safer anode material than graphite, has been investigated, and the authors demonstrate that (001)-faceted TiO 2 nanosheets display better electrochemical energy storage performance, higher charge/discharge rates, larger capacity, and improved stability over sphericalTiO2 nanoparticles.
Abstract: The influence of surface morphology on the lithium-ion battery performance of TiO2, a safer anode material than graphite, has been investigated. We demonstrate that (001)-faceted TiO2 nanosheets display better electrochemical energy storage performance, higher charge/discharge rates, larger capacity, and improved stability over spherical TiO2 nanoparticles. The improvement is attributed to the smaller charge diffusion resistance in the TiO2 nanosheets as a result of increased lithium-ion insertion/extraction along the c-axis during the charge/discharge process for the (001)-faceted TiO2 nanosheets in comparison to spherical TiO2 nanoparticles.
TL;DR: In this paper, the influence of the amount of hydrogen fluoride (HF) on product formation from the hydrothermal reaction of titanium butoxide and concentrated HF is investigated, and the synergistic effect between TiO2 nanosheets and TiOF2 particles is shown.
Abstract: The influence of the amount of hydrogen fluoride (HF) on product formation from the hydrothermal reaction of titanium butoxide and concentrated HF is investigated. Low HF contents lead to a preference for the formation of small TiO2 nanoparticles, medium HF contents lead to a preference for TiO2 nanosheets, and high HF contents lead to a preference for large TiOF2 particles. Meanwhile, TiO2 nanosheets display higher activity in photocatalytic hydrogen generation than that of smaller TiO2 nanoparticles; this demonstrates the higher photocatalytic activity of (001) facets over others. The synergistic effect between TiO2 nanosheets and TiOF2 particles could improve the performance of TiO2 nanosheets owing to possible charge separation over their interface, although TiOF2 particles themselves barely show any activity.
TL;DR: These highly crystalline, thermally stable (under vacuum) nanowires are p-type conducting and have a hole mobility as high as 2 cm2 ’V-1 S-1 , which is 102 -105 times higher than previously reported values.
Abstract: [Cu(SCH3 )]∞ nanowires with lengths on the order of hundreds of micrometers were obtained with a facile method from the reaction of Cu(NO3 )2 ⋅3 H2 O, dimethyl sulfoxide (DMSO), and water under hydrothermal conditions within a large range of DMSO/water ratios and at various temperatures. These highly crystalline, thermally stable (under vacuum) nanowires are p-type conducting and have a hole mobility as high as 2 cm2 V-1 S-1 , which is 102 -105 times higher than previously reported values. The high hole mobility may demonstrate their promising future in various electronic-device applications.