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61.
《Comptes Rendus Chimie》2014,17(7-8):641-655
Since the initial discovery of ordered mesoporous silica in early 1990s, considerable innovations were achieved regarding their synthesis, characterization and applications. One of the best outcomes of these intense research efforts is the development of a solid templating method called “nanocasting”, which is based on using mesoporous silica (or carbon) as a rigid template. This solid-to-solid replication method opened the pathway for synthesizing high surface area non-silica mesostructured materials that are challenging to obtain through conventional self-assembly processes which are based on amphiphilic soft structure-directing agents. In particular, the replicated metal oxide mesostructures obtained by this method were found to be highly versatile for a wide range of applications, especially in catalysis, owing to their large specific surface area. Furthermore, the nanocasting method is particularly suited for the synthesis of mixed metal compositions, favored by the possible confinement of mixed precursors in the nanopores of the template. In this account, we discuss some of the recent developments regarding the synthesis of nanocast mixed metal oxides and their perspectives of catalytic applications. It is here the choice of the authors to place emphasis on a few representative examples of compositions (e.g., non-noble metal-based catalysts, perovskites) and catalytic reactions (e.g., hydrogen production, gas-phase oxidation). 相似文献
62.
A label-free DNA-based electrochemical biosensor owning high sensitivity and selectivity has been established for detecting bisphenol A in a wide range of applications. Coupling the high electrochemical performance of graphene oxide-thionine-Au nanomaterial with the specific binding capacity of the aptamers to BPA, the monitoring of trace amount of BPA was realized, the detection limit was 3.3 pg ⋅ mL−1 with strong anti-interference. Besides, using molecular docking, it was found that BPA binds to the bases DC-49, DC-51, DG-52, DG-53 and DA-63 on the aptamer via hydrogen bonding and π-π stacking interactions. Finally, the biosensor had been successfully applied in different real samples. 相似文献
63.
Mahitha Udayakumar Bilal El Mrabate Tamás Koós Katalin Szemmelveisz Ferenc Kristály Máté Leskó Ádám Filep Róbert Géber Mateusz Schabikowski Péter Baumli János Lakatos Pál Tóth Zoltán Németh 《Arabian Journal of Chemistry》2021,14(7):103214
Carbon foams have gained significant attention due to their tuneable properties that enable a wide range of applications including catalysis, energy storage and wastewater treatment. Novel synthesis pathways enable novel applications via yielding complex, hierarchical material structure. In this work, activated carbon foams (ACFs) were produced from waste polyurethane elastomer templates using different synthesis pathways, including a novel one-step method. Uniquely, the produced foams exhibited complex structure and contained carbon microspheres. The ACFs were synthesized by impregnating the elastomers in an acidified sucrose solution followed by direct activation using CO2 at 1000 ℃. Different pyrolysis and activation conditions were investigated. The ACFs were characterized by a high specific surface area (SBET) of 2172 m2/g and an enhanced pore volume of 1.08 cm3/g. Computer tomography and morphological studies revealed an inhomogeneous porous structure and the presence of numerous carbon spheres of varying sizes embedded in the porous network of the three-dimensional carbon foam. X-ray diffraction (XRD) and Raman spectroscopy indicated that the obtained carbon foam was amorphous and of turbostratic structure. Moreover, the activation process enhanced the surface of the carbon foam, making it more hydrophilic via altering pore size distribution and introducing oxygen functional groups. In equilibrium, the adsorption of methylene blue on ACF followed the Langmuir isotherm model with a maximum adsorption capacity of 592 mg/g. Based on these results, the produced ACFs have potential applications as adsorbents, catalyst support and electrode material in energy storage systems. 相似文献
64.
二维过渡金属硫属化合物(TMDs)因具有可调带隙、 谷电子学性质和高催化活性等优点, 在电子学、 光电子学和能源相关领域受到广泛关注. 为了实现以上应用, 实现大面积、 厚度均匀TMDs薄膜的批量制备至关重要. 化学气相沉积法(CVD)是制备大面积均匀、 高质量二维材料普遍使用的方法. 本文从前驱体的供给和衬底的设计两个角度, 总结了目前合成大面积TMDs薄膜的CVD方法, 并讨论了高质量TMDs的生长机制和参数优化方法; 介绍了高质量TMDs在电子学、 光电子学和电/光催化等方面的应用; 讨论了目前合成大面积均匀、 高质量TMDs所面临的挑战, 并对该领域的发展方向进行了展望. 相似文献
65.
为了提高像移测量精度,针对机载航空摆扫相机提出一种坐标变换法和图像相关法相结合的像移测量方法。利用坐标变换法得到初始像移速度,利用图像联合变换相关法对像移速度残差进行补偿。联合图像通过一个面阵CCD获得,该面阵CCD放置在相机焦平面上并与成像线阵TDI CCD平行,其输出的当前图像与参考图像合并构成联合图像进行二维空间联合变换相关运算,得到像移修正矢量。对该矢量分别在相机摆扫方向和载机飞行方向进行分解,从而得到摆扫像移和前向像移的修正量。仿真实验结果表明,在输入图像信噪比为4 dB时,像移测量误差在0.1 pixel以内。 相似文献
66.
Vipin Amoli Rashmi Tiwari Arghya Dutta Prof. Asim Bhaumik Dr. Anil Kumar Sinha 《Chemphyschem》2014,15(1):187-194
Structurally thermostable mesoporous anatase TiO2 (m‐TiO2) nanoparticles, uniquely decorated with atomically dispersed SiO2, is reported for the first time. The inorganic Si portion of the novel organosilane template, used as a mesopores‐directing agent, is found to be incorporated in the pore walls of the titania aggregates, mainly as isolated sites. This is evident by transmission electron microscopy and high‐angle annular dark field scanning transmission electron microscopy, combined with electron dispersive X‐ray spectroscopy. This type of unique structure provides exceptional stability to this new material against thermal collapse of the mesoporous structure, which is reflected in its high surface area (the highest known for anatase titania), even after high‐temperature (550 °C) calcination. Control of crystallite size, pore diameter, and surface area is achieved by varying the molar ratios of the titanium precursor and the template during synthesis. These mesoporous materials retain their porosity and high surface area after template removal and further NaOH/HCl treatment to remove silica. We investigate their performance for dye‐sensitized solar cells (DSSCs) with bilayer TiO2 electrodes, which are prepared by applying a coating of m‐TiO2 onto a commercial titania (P25) film. The high surface area of the upper mesoporous layer in the P25–m‐TiO2 DSSC significantly increases the dye loading ability of the photoanode. The photocurrent and fill factor for the DSSC with the bilayer TiO2 electrode are greatly improved. The large increase in photocurrent current (ca. 56 %) in the P25–m‐TiO2 DSSC is believed to play a significant role in achieving a remarkable increase in the photovoltaic efficiency (60 %) of the device, compared to DSSCs with a monolayer of P25 as the electrode. 相似文献
67.
A series of high surface area graphitic carbon materials (HSGCs) were prepared by ball-milling method. Effect of the graphitic degree of HSGCs on the catalytic performance of Ba-Ru-K/HSGC-x (x is the ball-milling time in hour) catalysts was studied using ammonia synthesis as a probe reaction. The graphitic degree and pore structure of HSGC-x supports could be successfully tuned via the variation of ball-milling time. Ru nanoparticles of different Ba-Ru-K/HSGC-x catalysts are homogeneously distributed on the supports with the particle sizes ranging from 1.6 to 2.0 nm. The graphitic degree of the support is closely related to its facile electron transfer capability and so plays an important role in improving the intrinsic catalytic performance of Ba-Ru-K/HSGC-x catalyst. 相似文献
68.
69.
碳纳米管电极上原位沉积Pt纳米颗粒 总被引:1,自引:0,他引:1
本文利用原位离子交换法制备了碳纳米管(CNTs)载铂(Pt/CNTs)电极. X射线光电子能谱分析表明, Pt通过离子交换载于电化学功能化的CNTs表面. 扫描电镜照片显示, Pt高度分散于CNTs表面. X射线衍射分析表明, Pt的粒径约为4.0 nm. 离子交换法所制Pt/CNTs电极的电化学表面积和Pt的利用率均大于传统Pt/CNTs电极(Pt粒径约为2.5 nm), 其对氧还原的催化活性高于传统电极. 这归因于离子交换法所制电极的特殊结构,即Pt普遍载于电化学活性位上. 相似文献
70.