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<正>SnO_2 nanorods were deposited on the Si substrates in an aqueous solution containing both SnCl_4 and CO(NH_2)_2.It is found that different self-assembled patterns of SnO_2 nanorods can be obtained by changing the deposition conditions such as the molar ratio of CO(NH_2)_2 to SnCl_4 and the pretreatment of the substrate.Scattered SnO_2 nanorods,for example,can be changed into flower-like patterns when the molar ratio of CO(NH_2)_2 to SnCl_4 is raised,and well-aligned nanorod arrays can be formed when the pretreatment of the substrate is changed.In addition,some interesting patterns,e.g.tree-like patterns,can also be observed. 相似文献
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本文以Triton X-100/C10H21OH/H2O体系层状溶致液晶为模板,Ca(NO3)2和(NH4)2HPO4为反应物,在一定的pH条件下,通过三元相图确定了层状液晶单相区域,并合成了羟基磷灰石(HA)纳米颗粒。用傅立叶红外光谱(FTIR),X射线衍射(XRD)和透射电子显微镜(TEM)对产物进行了表征。并考察了不同助表面活性剂浓度和不同表面活性剂浓度对产物的形貌和尺寸的影响。结果表明所制备的HA纳米颗粒平均直径为8~10nm、长度在100nm左右,呈针状。助表面活性剂浓度对HA形貌及尺寸影响不大,但是在一定范围内改变表面活性剂浓度可以起到调控HA纳米颗粒形貌和尺寸的作用。 相似文献
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Ying Liu Chong‐an Di Dr. Chunyan Du Yunqi Liu Prof. Kun Lu Wenfeng Qiu Dr. Gui Yu Prof. 《Chemistry (Weinheim an der Bergstrasse, Germany)》2010,16(7):2231-2239
A series of fused thiophenes composed of fused α‐oligothiophene units as building blocks, end‐capped with either styrene or 1‐pentyl‐4‐vinylbenzene groups, has been synthesized through Stille coupling reactions. The compounds have been fully characterized by means of 1H NMR spectrometry, high‐resolution mass spectrometry, and elemental analysis. The molecules present a trans–trans configuration between their double bonds, which has been verified and confirmed by Fourier‐transform infrared spectroscopy and single‐crystal X‐ray diffraction analysis. The X‐ray crystal structures showed π–π overlap and sulfur–sulfur interactions between the adjacent molecules. The decomposition temperatures were all found to be above 300 °C, indicating that compounds of this series possess excellent thermal stability. The fact that no phase transition occurs at low temperature indicates that they should be well‐suited for application in devices. Moreover, they possess low HOMO energy levels, based on cyclic voltammetry measurements, and suitable energy gaps, as determined from their thin‐film UV/Vis spectra. Thin‐film X‐ray diffraction analysis and atomic force microscopy revealed high crystallinity on supporting substrates. In addition, as the substrate temperature has a significant influence on the morphology and the degree of crystallinity, the device performance could be optimized by varying the substrate temperature. These materials were found to exhibit optimal field‐effect performance, with a mobility of 0.17 cm2 V?1 s?1 and an on/off ratio of 105, at a substrate temperature of 70 °C. 相似文献
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木质素是一种天然芳香族聚合物,约占木质纤维素的30%,是唯一通过裂解C―O醚键和C―C键生产芳香族化学品或液体燃料的可再生芳香族资源。迄今为止,对木质素氢解制备有价值化合物的研究主要集中在相对不稳定的C―O键的裂解上,这限制了木质素氢解的效率。采用水热法和湿浸渍法制备了多功能Pt/NbPWO催化剂。通过破坏碱木质素中的C―O键和C―C键,可以得到产率为18.02%的芳香族单体。该反应不仅可以断裂木质素聚合物中醚键,同时也可以断裂部分关键的C―C键。其氢解机理可能是丰富的Brønsted酸和Lewis酸位点参与了C―C的活化。此外,重点分析载体和Pt物种在Pt/NbPWO催化剂中的协同作用。 相似文献
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Jia Yan Ting Wang Siyao Qiu Zhilong Song Wangqin Zhu Xianhu Liu Jiabiao Lian Chenghua Sun Huaming Li 《Journal of Energy Chemistry》2022,(2):548-555
Two-dimensional carbon nitride(2 D-C3 N4)nanosheets are promising materials in photocatalytic water splitting,but still suffer from easy agglomeration and fast photogene rated electron-hole pairs recombination.To tackle this issue,herein,a hierarchical Nb2 O5/2 D-C3 N4 heterostructure is precisely constructed and the built-in electric field between Nb2O5 and 2 D-C3 N4 can provide the driving force to separate/transfer the charge carriers efficiently.Moreover,the strongly Lewis acidic Nb2O5 can adsorb TEOA molecules on its surface at locally high concentrations to facilitate the oxidation reaction kinetics under irradiation,resulting in efficient photogene rated electrons-holes separation and exceptional photocatalytic hydrogen evolution.As expected,the champion Nb2O5/2 D-C3N4 heterostructure achieves an exceptional H2 evolution rate of 31.6 mmol g-1 h-1,which is 213.6 times and 4.3 times higher than that of pristine Nb2O5 and2 D-C3N4,respectively.Moreover,the champion heterostructure possesses a high apparent quantum efficiency(AQE)of 45.08%atλ=405 nm and superior cycling stability.Furthermore,a possible photocatalytic mechanism of the energy band alignment at the hetero-interface is proposed based on the systematical characterizations accompanied by density functional theory(DFT)calculations.This work paves the way for the precise construction of a high-quality heterostructured photocatalyst with efficient charge separation to boost hydrogen production. 相似文献
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Zhao Bencheng Yue Xuejie Tian Qiong Qiu Fengxian Zhang Tao 《Cellulose (London, England)》2022,29(3):1981-1992
Cellulose - The energy consumption for building cooling occupies non-ignorable part of global energy consumption, causing the increasing aggravation of energy crisis and environmental... 相似文献