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| 2. |
- Zhu, Jiefang, 1973, et al.
(författare)
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Nanostructured materials for photocatalytic hydrogen production
- 2009
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Ingår i: Current Opinion in Colloid and Interface Science. - : Elsevier BV. - 1359-0294 .- 1879-0399. ; 14:4, s. 260-269
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Tidskriftsartikel (refereegranskat)abstract
- Photocatalytic hydrogen (H-2) production represents a very promising but challenging contribution to a clean, sustainable and renewable energy system. The photocatalyst material plays a key role in photocatalytic H-2 production, and it has proven difficult to obtain corrosion resistant, chemically stable, visible light harvesting and highly efficient photocatalysts, which have their band edges matching the O-2 and H-2 production levels. Nanoscience and nanotechnology are opening a new vista in the development of highly active, nanostructured photocatalysts with large surface areas for optimized light absorption, minimized distances (or times) for charge-carrier transport, and further favorable properties. Our focus here is on recently developed nanostructured photocatalysts. In particular. the particle size, chemical composition (including dopants), microstructure, crystal phase. morphology, surface modification, bandgap and flat-band potential of the nanophotocatalysts have shown a visible effect on photocatalytic H-2 production rates, which may be further increased by adding sensitizers, cocatalysts or scavengers. Finally, potential directions required to push this research field a step further are highlighted. (
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| 3. |
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| 4. |
- Li, Shaowen, et al.
(författare)
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A Multiscale, Dynamic Elucidation of Li Solubility in the Alloy and Metallic Plating Process
- 2023
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Ingår i: Advanced Materials. - 0935-9648 .- 1521-4095. ; 35:47
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Tidskriftsartikel (refereegranskat)abstract
- Li-containing alloys and metallic deposits offer substantial Li+ storage capacities as alternative anodes to commercial graphite. However, the thermodynamically in sequence, yet kinetically competitive mechanism between Li solubility in the solid solution and intermediate alloy-induced Li deposition remains debated, particularly across the multiple scales. The elucidation of the mechanism is rather challenging due to the dynamic alloy evolution upon the non-equilibrium, transient lithiation processes under coupled physical fields. Here, influential factors governing Li solubility in the Li-Zn alloy are comprehensively investigated as a demonstrative model, spanning from the bulk electrolyte solution to the ion diffusion within the electrode. Through real-time phase tracking and spatial distribution analysis of intermediate alloy/Li metallic species at varied temperatures, current densities and particle sizes, the driving force of Li solubility and metallic plating along the Li migration pathway are probed in-depth. This study investigates the correlation between kinetics (pronounced concentration polarization, miscibility gap in lattice grains) and rate-limiting interfacial charge transfer thermodynamics in dedicating the Li diffusion into the solid solution. Additionally, the lithiophilic alloy sites with the balanced diffusion barrier and Li adsorption energy are explored to favor the homogeneous metal plating, which provides new insights for the rational innovation of high-capacity alloy/metallic anodes.
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| 5. |
- Li, Shaowen, et al.
(författare)
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A Multiscale, Dynamic Elucidation of Li Solubility in the Alloy and Metallic Plating Process
- 2023
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Ingår i: Advanced Materials. - : Wiley-VCH Verlagsgesellschaft. - 0935-9648 .- 1521-4095. ; 35:47
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Tidskriftsartikel (refereegranskat)abstract
- Li-containing alloys and metallic deposits offer substantial Li+ storage capacities as alternative anodes to commercial graphite. However, the thermodynamically in sequence, yet kinetically competitive mechanism between Li solubility in the solid solution and intermediate alloy-induced Li deposition remains debated, particularly across the multiple scales. The elucidation of the mechanism is rather challenging due to the dynamic alloy evolution upon the non-equilibrium, transient lithiation processes under coupled physical fields. Here, influential factors governing Li solubility in the Li-Zn alloy are comprehensively investigated as a demonstrative model, spanning from the bulk electrolyte solution to the ion diffusion within the electrode. Through real-time phase tracking and spatial distribution analysis of intermediate alloy/Li metallic species at varied temperatures, current densities and particle sizes, the driving force of Li solubility and metallic plating along the Li migration pathway are probed in-depth. This study investigates the correlation between kinetics (pronounced concentration polarization, miscibility gap in lattice grains) and rate-limiting interfacial charge transfer thermodynamics in dedicating the Li diffusion into the solid solution. Additionally, the lithiophilic alloy sites with the balanced diffusion barrier and Li adsorption energy are explored to favor the homogeneous metal plating, which provides new insights for the rational innovation of high-capacity alloy/metallic anodes.
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| 6. |
- Ma, M. G., et al.
(författare)
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A facile solvothermal route to synthesis of gamma-alumina with bundle-like and flower-like morphologies
- 2009
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Ingår i: Materials Letters. - : Elsevier BV. - 1873-4979 .- 0167-577X. ; 63:11, s. 881-883
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Tidskriftsartikel (refereegranskat)abstract
- Boehmite with bundle-like morphology assembled from nanofibres has been successfully synthesized by solvothermal method from AlCl3 center dot 6H(2)O in ethylene glycol (EG) at 200 degrees C for 10 h. Using 1,4-Butanediol instead of EG, the Al-11(OH)(30)Cl-3 with flower-like morphology assembled from nanosheets was obtained at 200 degrees C for 6 h. The gamma-alumina with similar morphology was obtained by thermal decomposition of the boehmite or Al-11(OH)(30)Cl-3 at 500 degrees C for 3 h in air. The products were characterized by X-ray powder diffraction (XRD), Fourier transform infrared spectrometry (FTIR), transmission electron microscopy (TEM), and thermogravimetric analysis (TG). The method is simple and does not need any surfactant or template or base. (C) 2009 Elsevier B.V. All rights reserved.
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| 7. |
- Ma, M. G., et al.
(författare)
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Hydrothermal-polyol route to synthesis of beta-Ni(OH)(2) and NiO in mixed solvents of 1,4-butanediol and water
- 2009
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Ingår i: Materials Letters. - : Elsevier BV. - 1873-4979 .- 0167-577X. ; 63:21, s. 1791-1793
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Tidskriftsartikel (refereegranskat)abstract
- The beta-Ni(OH)(2) with flower-like morphology assembled from nanosheets has been successfully synthesized by a hydrothermal-polyol method from Ni(CH3COO)(2)center dot 4H(2)O in mixed solvents of 1,4-butanediol and water at 200 degrees C for 24 h. The NiO with similar morphology was obtained by a simple thermal decomposition of the precursor (beta-Ni(OH)(2)) at 400 degrees C for 3 h in air. The products were characterized by X-ray powder diffraction (XRD), field-emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), selected area electron diffraction (SAED), thermogravimetric analysis (TG) and differential scanning calorimetric analysis (DSC). We expect that this hydrothermal-polyol method may be extended to the preparation of nanostructures of other kinds of metal oxides. (C) 2009 Elsevier B.V. All rights reserved.
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| 8. |
- Sellappan, Raja, 1981, et al.
(författare)
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Preparation and characterization of TiO2/carbon composite thin films with enhanced photocatalytic activity
- 2011
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Ingår i: Journal of Molecular Catalysis A. - : Elsevier BV. - 1381-1169 .- 1873-314X. ; 335:1-2, s. 136-144
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Tidskriftsartikel (refereegranskat)abstract
- Composite TiO2/carbon thin films prepared by physical vapor deposition techniques on fused silica substrates show enhanced photocatalytic activity towards decomposition of methanol to CO2 and water, as compared to pure TiO2 films of similar thickness. Raman and XRD measurements confirm that annealed TiO2 films exhibit anatase structure while the carbon layer becomes graphitic. Characteristic for the composite films is an enhanced optical absorption in the visible range. The presence of the carbon film causes a shift of the TiO2 absorption edge and modifies its grain size to be smaller. We hypothesize that the observed enhancement of photocatalytic activity is due to synergy effects at the carbon/TiO2 interface, resulting in smaller titania crystallite size and anisotropic charge carrier transport, which in turn reduces their recombination probability.
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| 9. |
- Zhang, Fengling, et al.
(författare)
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Ordered mesoporous Ag-TiO2-KIT-6 heterostructure: synthesis, characterization and photocatalysis
- 2009
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Ingår i: Journal of Materials Chemistry. - : Royal Society of Chemistry (RSC). - 1364-5501 .- 0959-9428. ; 19:18, s. 2771-2777
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Tidskriftsartikel (refereegranskat)abstract
- Ordered mesoporous Ag-TiO2-KIT-6 heterostructured nanocrystals were successfully synthesized by a template-based method, where a layer of TiO2 and Ag2O nanoparticles were deposited on cubic (Ia3d) silica (KIT-6) in an orderly manner; at the same time, the formed Ag2O nanoparticles were photolyzed to metallic Ag nanoparticles. Our results show that Ag-TiO2-KIT-6 is an ordered mesoporous composite material, which is composed of Ag-TiO2 heterostructures and the amorphous KIT-6 template. In addition, Ag-TiO2-KIT-6 possesses the highest photocatalytic activity among the as-synthesized photocatalysts, which can be attributed to the Ag-TiO2 heterojunctions and the excellent texture: (1) Ag-TiO2 heterojunctions improve the separation of photogenerated electron-hole pairs due to the potential energy differences between Ag and TiO2 nanocrystals, thus enhancing the photocatalytic activity; (2) the Ag-TiO2-KIT-6 sample possesses a high BET surface area and a large number of ordered pore channels, which facilitate adsorption and transportation of dye molecules, also leading to higher photocatalytic activity. It was also found that the Ag-TiO2 heterostructure plays a more important role in enhancing the photocatalytic activity than high BET surface area.
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| 10. |
- Zheng, L. R., et al.
(författare)
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Network Structured SnO2/ZnO Heterojunction Nanocatalyst with High Photocatalytic Activity
- 2009
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Ingår i: Inorganic Chemistry. - : American Chemical Society (ACS). - 0020-1669 .- 1520-510X. ; 48:5, s. 1819-1825
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Tidskriftsartikel (refereegranskat)abstract
- A network-structured SnO2/ZnO heterojunction nanocatalyst with high photocatalytic activity was successfully synthesized through a simple two-step solvothermal method. The as-synthesized samples are characterized by X-ray diffraction, X-ray photoelectron spectroscopy, transmission electron microscopy, scanning electron microscopy, N-2 physical adsorption, and UV-vis spectroscopy. The results show that the SnO2/ZnO sample with a molar ratio of Sn/Zn = 1 is a mesoporous composite material composed of SnO2 and ZnO. The photocatalytic activity of SnO2/ZnO heterojunction nanocatalysts for the degradation of methyl orange is much higher than those of solvothermally synthesized SnO2 and ZnO samples, which can be attributed to the SnO2-ZnO heterojunction, the pore structure, and higher Brunauer-Emmeff-Teller (BET) surface area of the sample: (1) The SnO2-ZnO heterojunction improves the separation of photogenerated electron-hole pairs due to the potential energy differences between SnO2 and ZnO, thus enhancing the photocatalytic activity. (2) The SnO2/ZnO sample might possess more surface reaction sites and adsorb and transport more dye molecules due to the higher BET surface area and many pore channels, also leading to higher photocatalytic activity.
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| 11. |
- Zheng, Y. H., et al.
(författare)
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Photocatalytic activity of Ag/ZnO heterostructure nanocatalyst: Correlation between structure and property
- 2008
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Ingår i: Journal of Physical Chemistry C. - : American Chemical Society (ACS). - 1932-7447 .- 1932-7455. ; 112:29, s. 10773-10777
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Tidskriftsartikel (refereegranskat)abstract
- Ag/ZnO heterostructure nanocatalysts with Ag content of 1 wt % are successfully prepared through three different simple methods, where chemical reduction and photolysis reaction are adopted to fabricate the heterostructure. The dispersity of Ag clusters and/or nanoparticles in Ag/ZnO nanocatalyst is investigated by EDX mapping and XPS techniques. The experimental results show that deposition-precipitation is an efficient method to synthesize Ag/ZnO nanocatalyst with highly dispersed Ag clusters and/or nanoparticles; the photocatalytic activity of Ag/ZnO photocatalysts mainly depends on the dispersity of metallic Ag in Ag/ZnO nanocatalyst; the higher the dispersity of metallic Ag in Ag/ZnO nanocatalyst is, the higher the photocatalytic activity of Ag/ZnO photocatalyst should be. In addition, it is also found that the dispersity of Ag/ZnO photocatalyst in the dye solution is another key factor for liquid-phase photocatalysis due to the UV-light utilizing efficiency. The higher the UV-light utilizing efficiency is, the higher the photocatalytic activity of Ag/ZnO heterostructure photocatalyst should be.
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