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101.
Zixuan Ding Haihua Hu Juan Xu Ping Lin Can Cui Degui Qian Peng Wang Lingbo Xu Jiaqi Pan Chaorong Li 《International Journal of Hydrogen Energy》2018,43(29):13190-13199
We report the synthesis of TiO2 hierarchical spheres (THS) with large specific surface area via a facile one-pot solvothermal method. The as-prepared THS are self-assembled by ultrathin TiO2 nanosheets with thickness of several nanometers and they show a uniform spherical morphology with an average size of 500–700 nm. However, the as-prepared light yellow THS exhibit inferior photocatalytic activity for hydrogen evolution from water splitting due to the poor crystallization of TiO2 and the existence of oxygen vacancies. Significantly, a subsequent thermal treatment improves the crystallinity of THS, reduces the oxygen vacancies, and thereby enhances the photocatalytic performance. It demonstrates that the sample annealed at 550 °C (THS550) exhibits the highest photocatalytic activity, about 5 times higher than that of commercial TiO2 nanoparticles (CTiO2). Moreover, the THS550 sample loaded with 1 wt% Pt exhibits an hydrogen evolution rate as high as 17.9 mmol h?1g?1, and the corresponding apparent quantum efficiency has been determined to be 28.46% under 350 nm light irradiation. 相似文献
102.
Jian Guan Jianhua Wu Daochuan Jiang Xianjun Zhu Runnan Guan Xunyong Lei Pingwu Du Hualing Zeng Shangfeng Yang 《International Journal of Hydrogen Energy》2018,43(18):8698-8706
Molybdenum disulfide (MoS2) as a representative transition-metal dichalcogenide (TMD) has been extensively used as a noble-metal-free cocatalyst for photocatalytic hydrogen (H2) production, but suffers from poor photocatalytic activity due to the catalytic inactivity of its basal plane. Herein, by bounding another metal-free cocatalyst, C60, with MoS2, we report the first MoS2-C60 hybrid featuring a van der Waals heterostructure prepared via a facile and eco-friendly solid-state mechanochemical route. C60 bounding onto the edge of MoS2 nanosheets leads to the decreases of both the number of layers and the size of MoS2 nanosheets, as well as a negative shift of the conduction band minimum along with a positive shift of valance band maximum relative to the bulk MoS2 and MoS2 ball-milled without C60 (MoS2-BM). Under the optimized weight ratio of MoS2:C60 (1:1) in the raw mixture subject to ball-milling, MoS2-C60 hybrid containing 2.8 wt% C60 shows an exceptional visible light photocatalytic H2 production rate of 6.89 mmol h?1 g?1 in the presence of a photosensitizer Eosin Y (EY), which is significantly enhanced relative to the bulk MoS2 and pristine C60, both of which show almost no photocatalytic H2 activity. Thus, the synergistic enhancement of photocatalytic activities of both MoS2 and C60 is revealed. 相似文献
103.
Xiaoxiang Xu Gang Liu Chamnan Randorn John T.S. Irvine 《International Journal of Hydrogen Energy》2011,36(21):13501-13507
A highly active photocatalyst based on g-C3N4 coated SrTiO3 has been synthesized simply by decomposing urea in the presence of SrTiO3 at 400 °C. The catalyst demonstrates a high H2 production rate ∼440 μmol h−1/g catalyst in aqueous solution under visible light irradiation, which is much higher than conventional anion doped SrTiO3 or physical mixtures of g-C3N4 and SrTiO3. The improved photocatalytic activity can be ascribed to the close interfacial connections between g-C3N4 and SrTiO3 where photo-generated electron and holes are effectively separated. The newly synthesized catalyst also exhibited a stable performance in the repeated experiments. 相似文献
104.
Young-E Moon Gowun JungJumi Yun Hyung-Il Kim 《Materials Science and Engineering: B》2013,178(17):1097-1103
Poly(vinyl alcohol)/poly(acrylic acid)/TiO2/graphene oxide nanocomposite hydrogels were prepared using radical polymerization and condensation reaction for the photocatalytic treatment of waste water. Graphene oxide was used as an additive to improve the photocatalytic activity of poly(vinyl alcohol)/poly(acrylic acid)/TiO2 nanocomposite hydrogels. Both TiO2 and graphene oxide were immobilized in poly(vinyl alcohol)/poly(acrylic acid) hydrogel matrix for an easier recovery after the waste water treatment. The photocatalytic activity of poly(vinyl alcohol)/poly(acrylic acid)/TiO2/graphene oxide nanocomposite hydrogels was evaluated on the base of the degradation of pollutants by using UV spectrometer. The improved removal of pollutants was due to the two-step mechanism based on the adsorption of pollutants by nanocomposite hydrogel and the effective decomposition of pollutants by TiO2 and graphene oxide. The highest swelling of nanocomposite hydrogel was observed at pH 10 indicating that poly(vinyl alcohol)/poly(acrylic acid)/TiO2/graphene oxide nanocomposite hydrogels were suitable as a promising system for the treatment of basic waste water. 相似文献
105.
AbstractThis review article summarizes recent developments in mesoporous titania materials, particularly in the fields of morphology control and applications. We first briefly introduce the history of mesoporous titania materials and then review several synthesis approaches. Currently, mesoporous titania nanoparticles (MTNs) have attracted much attention in various fields, such as medicine, catalysis, separation and optics. Compared with bulk mesoporous titania materials, which are above a micrometer in size, nanometer-sized MTNs have additional properties, such as fast mass transport, strong adhesion to substrates and good dispersion in solution. However, it has generally been known that the successful synthesis of MTNs is very difficult owing to the rapid hydrolysis of titanium-containing precursors and the crystallization of titania upon thermal treatment. Finally, we review four emerging fields including photocatalysis, photovoltaic devices, sensing and biomedical applications of mesoporous titania materials. Because of its high surface area, controlled porous structure, suitable morphology and semiconducting behavior, mesoporous titania is expected to be used in innovative applications. 相似文献
106.
Yoshio Nosaka Masami Matsushita Junichi Nishino Atsuko Nosaka 《Science and Technology of Advanced Materials》2013,14(2):143-148
In order to utilize visible light in photocatalytic reactions, nitrogen atoms were doped in commercially available photocatalytic TiO2 powders by using an organic compound such as urea and guanidine. Analysis by X-ray photoelectron spectroscopy (XPS) indicated that N atoms were incorporated into two different sites of the bulk phase of TiO2. A significant shift of the absorption edge to a lower energy and a higher absorption in the visible light region were observed. These N-doped TiO2 powders exhibited photocatalytic activity for the decomposition of 2-propanol in aqueous solution under visible light irradiation. The photocatalytic activity increased with the decrease of doped N atoms in O site, while decreased with decrease of the other sites. Degradation of photocatalytic activity based on the release of nitrogen atoms was observed for the reaction in the aqueous suspension system. 相似文献
107.
Shihong Xu Jian Yuan Jianwei Shi Mingxia Chen 《Science and Technology of Advanced Materials》2013,14(1-2):40-46
A magnetically separable photocatalyst Bi12TiO20/SiO2/NiFe2O4 (BSN) with a typical ferromagnetic hysteresis was prepared by a simple process: the magnetic 200 wt% SiO2/NiFe2O4 (SN) dispersion prepared by a liquid catalytic phase transformation method and the visible-light-active photocatalyst Bi12TiO20 prepared by a simple coprecipitation processing were mixed, sonificated, dried, and calcined at 550°C. The prepared photocatalyst showed high photocatalytic activity for the degradation of methyl orange in water under UV irradiation and visible-light irradiation (λ>400 nm), and it was easy to be separated from a slurry-type photoreactor under the application of an external magnetic field, being one of promising photocatalysts for wastewater treatment. Transmission electron microscope (TEM) and X-ray diffractometer (XRD) were used to characterize the structure of the photocatalyst, indicating that the magnetic SN particles adhered to the surface of the Bi12TiO20 congeries. SiO2 layer round the surface of NiFe2O4 nanoparticles prevented effectively the injection of charges from TiO2 particles to NiFe2O4, which gave rise to the increase in photocatalytic activity. 相似文献
108.
Naixu Li Bingyao Zhou Penghui Guo Jiancheng Zhou Dengwei Jing 《International Journal of Hydrogen Energy》2013
Up to now, most of the semiconductor photocatalysts can only achieve their high photocatalytic activity for hydrogen production with the loading of noble metals, such as Pt or Ru, as cocatalysts, which drastically increases the total cost of the designed photocatalyst. Herein, we report the design and fabrication of a highly efficient Cd0.5Zn0.5S photocatalyst decorated with nanosized NiS surface heterojunctions. The hydrogen evolution rate over this photocatalyst reached 1.4 mmol/h, with a remarkable quantum yield of 33.9%. This efficiency is even much higher than many noble metal loaded photocatalysts. In this hybrid photocatalyst, the nanosized NiS on the surface can serve as electron trapping sites, by which, photogenerated electrons were extracted from Cd0.5Zn0.5S substrate, leading to spatially separated photoreduction and oxidation reactions. More interestingly, it was found that NiS played a similar role as noble metal, providing active sites for proton reduction, and hence efficiently enhancing the overall hydrogen production rate. Our work demonstrates the possibility of substitution of noble metal cocatalyst by a properly engineered surface hetero-junction to achieve efficient and low cost photocatalytic hydrogen production. 相似文献
109.
In this study, ternary P25/GO/Pt hybrid photocatalysts are prepared in different orders, using Degussa's TiO2 (P25), graphene oxide (GO), chloroplatinic acid as precursor. The prepared catalysts were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), fourier transform infrared spectroscopy (FT-IR) and X-ray photoelectron spectroscopy (XPS). This work is first time to compare the hydrogen production of the ternary P25/GO/Pt hybrid photocatalysts prepared in different orders. We focus on studying the introduction of GO and find that the quantity of introduced GO and electronic transfer path play an important role in photocatalytic activity on ternary P25/GO/Pt hybrid catalysts. When the proper Pt particle loaded on the flat surface of GO which was 0.5wt% of P25, the highest H2 evolution was obtained. 相似文献
110.
Cheap and efficient photocatalysts were fabricated by simply mixing TiO2 nanoparticles (NPs) and CuO NPs. The two NPs combined with each other to form TiO2/CuO mixture in an aqueous solution due to the opposite surface charge. The TiO2/CuO mixture exhibited photocatalytic hydrogen production rate of up to 8.23 mmol h−1 g−1 under Xe lamp irradiation when the weight ratio of P25 to CuO was optimized to 10. Although the conduction band edge position of CuO NPs is more positive than normal hydrogen electrode, the TiO2/CuO mixture exhibited good photocatalytic hydrogen production performance because of the inter-particle charge transfer between the two NPs. The detailed mechanism of the photocatalytic hydrogen production is discussed. This mixing method does not require a complicated chemical process and allows mass production of the photocatalysts. 相似文献