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91.
92.
Nanocomposites of Tantalum‐Based Pyrochlore and Indium Hydroxide Showing High and Stable Photocatalytic Activities for Overall Water Splitting and Carbon Dioxide Reduction 下载免费PDF全文
Meng‐Chun Hsieh Guan‐Chang Wu Dr. Wei‐Guang Liu Prof. William A. Goddard III Prof. Dr. Chia‐Min Yang 《Angewandte Chemie (International ed. in English)》2014,53(51):14216-14220
Nanocomposites of tantalum‐based pyrochlore nanoparticles and indium hydroxide were prepared by a hydrothermal process for UV‐driven photocatalytic reactions including overall water splitting, hydrogen production from photoreforming of methanol, and CO2 reduction with water to produce CO. The best catalyst was more than 20 times more active than sodium tantalate in overall water splitting and 3 times more active than Degussa P25 TiO2 in CO2 reduction. Moreover, the catalyst was very stable while generating stoichiometric products of H2 (or CO) and O2 throughout long‐term photocatalytic reactions. After the removal of In(OH)3, the pyrochlore nanoparticles remained highly active for H2 production from pure water and aqueous methanol solution. Both experimental studies and density functional theory calculations suggest that the pyrochlore nanoparticles catalyzed the water reduction to produce H2, whereas In(OH)3 was the major active component for water oxidation to produce O2. 相似文献
93.
In this work, we demonstrate an in situ phase conversion from basic magnesium chloride(BMC) into magnesium hydroxide whisker by using polar organic solvent at low temperature. The morphology and phase composition of magnesium hydroxide whiskers prepared at different reaction temperature, alkali concentration and organic solvent were analyzed by X-ray diffraction(XRD) and scanning electronic microscope(SEM). It was found that when one of the organic solvents such as absolute ethyl alcohol, butanol, polyethylene glycol(PEG-400), acetone, et al. was selected as the template, the precursor BMC can transform into whisker-like magnesium hydroxide through precipitate transformation in low temperature and non-hydrothermal system. It can be reasonably explained that the regulation of Mg^2+ solubility by those organic solvents and the sustained release of Mg^2+ dissolution by organic adsorption played a significant role in the formation of magnesium hydroxide whisker via BMC whisker as the precursor. 相似文献
94.
The layered double hydroxides (LDHs) of Li and Al can be synthesized from the four polymorphs of Al(OH)3, namely gibbsite, bayerite, nordstrandite, and doyleite. The crystal structure of this class of compounds depends on the type of the precursor used due to their topotactic reaction mechanism. While the LDHs derived from gibbsite and bayerite yield different crystal structures, the incorporation of Li into nordstrandite was expected to yield new LDH structures different from those derived from gibbsite and bayerite. The structure of nordstrandite derived LDHs were however identical to that derived from the bayerite counterpart. The absence of symmetry in the interlayer of nordstrandite (C1) makes it unsuitable to accommodate the intercalating anions with different molecular symmetries. To make the interlayer gallery suitable for the anions, the metal hydroxide layers of the nordstrandite translate, transforming nordstrandite to bayerite. The bayerite with site symmetries Oh and C2 stabilizes the anions in the interlayer by hydrogen bonding. The transformation of nordstrandite to bayerite, when soaked in lithium salt solution is, therefore, a manifestation of the intercalating anions. 相似文献
95.
借助手持技术通过电化学方法测定乙醛与新制氢氧化铜反应的电压变化情况,揭示了该反应的本质,通过控制变量的思想探究了NaOH在该反应中所起的作用,并结合相关文献知识和实验对比进一步探究了乙醛与新制氢氧化铜反应产物的成分。 相似文献
96.
《Journal of Saudi Chemical Society》2020,24(10):715-732
The mechanistic aspects of improved aqueous removal of methyl orange (MO) dyes using high performance novel magnetic MgAlNi barium-ferrite (MgAlNi-BaFe) ternary double layer hydroxide (LDH) nanocomposites is reported in this study. Detailed surface characterization coupled with kinetic, equilibrium, thermodynamics and regeneration studies were undertaken under different operational conditions of temperature (298–318 K), initial concentration (20–100 mg/L), pH (2–6). The kinetic results show that MO sorption was mainly, associated with pseudo-second order and intra-particular diffusion process. The MO adsorption onto the MgAlNi-BaFe nanocomposites suggests a multi-layered sorption process that is endothermic and spontaneous in nature. The MO adsorption mechanism insight taken in cognizance of FTIR, XRD, pKa, zeta potential, the adsorbates surface functional groups and the adsorbate-adsorbent surface charges interactions suggest involvement of hydrogen bonding and n-π interactions, predominantly via physisorption process (ΔG° = −7.406 to −5.69 kJ/mol). The excellent adsorptive performance of the MgAlNi-BaFe adsorbents for removal of MO from water compared with other magnetic LDH nanocomposites was further elucidated via the MgAlNi-BaFe nanomaterials high rates of regeneration and superior performances for three successive desorption-adsorption cycles. This study demonstrates the high potentials of employing MgAlNi-BaFe nanomaterials for removal of dyes from water and wastewater. 相似文献
97.
The separation of the principal inorganic anions (bromide, carbonate, chlorate, chloride, fluoride, nitrate, nitrite, sulfate, phosphate) has been achieved using a capillary electrophoresis system with indirect UV detection at 260 nm. Several types of cationic surfactants (quaternary ammonium, phosphonium or methonium) were tested as electroosmotic flow modifiers and added to a chromatebased buffer prepared from potassium dichromate. The influence of many physicochemical parameters such as nature and concentration of cationic surfactant, buffer pH, dichromate concentration buffer, voltage and temperature upon the migration time of an analyte anion, peak efficiency, asymmetry factor, and finally resolution has been investigated. A linear relationship between the corrected area and the anion concentration in the 2.5–50 ppm range was obtained, thus allowing the quantitative analysis of anions in mineral water. Finally, by increasing the hydrodynamic injection time, the separation of inorganic anions at a low concentration level of 50 ng/ml was achieved without any loss of resolution. 相似文献
98.
A two-stage, no-mix anaerobic digester of 145 L capacity was used to investigate the effect of controlling the pH of the methanogenic
stage on the biogas production and the pollution potential reduction of acid cheese whey. The digester was operated at a 15-d
hydraulic retention time, and a temperature of 35°C. Controlling the pH of the methanogenic stage increased the biogas production
rate and methane yield by 77.77 and 289.00%, respectively. Reductions of up to 32.19, 44.44, and 35.86% in the COD, solids
and nitrogen were achieved. 相似文献
99.
100.