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1.
《Ceramics International》2022,48(14):19513-19526
Comprehensive control of processing techniques is primordial when fine-tuning the morphological features of titanium dioxide nanotube arrays (TNTs). This systematic review and meta-analysis compiled articles published from 2007 to date on the synthesis and growth mechanism of nanotubes fabricated via electrochemical anodization and evaluated the potential relationships between anodizing conditions and the resulting structures. Studies were gathered from the Science Direct online database, screened according to predefined criteria, and evaluated for their eligibility. Ninety-nine studies were assessed in the meta-analysis, 87 of them on tube length, 80 on tube diameter, and 33 on wall thickness. Multiple linear regression was performed to test if anodization parameters significantly predicted the resulting morphology of TiO2 nanotubular structures. Overall regression for the three responses was statistically significant (length: R2 = 0.487, p < 0.001; diameter: R2 = 0.899, p < 0.001; wall thickness: R2 = 0.792, p < 0.001). Applied potential was one of the main effects predicting all three responses (p < 0.001 in every model). Other important main predictors were anodizing time for tube length (p < 0.001), water percentage for tube diameter (p < 0.001) and ammonium fluoride (NH4F) concentration for wall thickness (p < 0.001). 相似文献
2.
《International Journal of Hydrogen Energy》2022,47(34):15480-15490
The rapid increase in energy consumption has severely rehabilitated human life urging to develop reliable and environmental friendly energy storage devices. Target oriented, systematic approach has been adopted to synthesis La doped CeO2 nanostructures with percentage as LaxCe1-xO2 (X = 0,1,3,5,7) for potential super capacitors applications. Morphological doping impact on H2 production, electrochemical and optical properties are thoroughly investigated. XRD studies revealed the crystalline phase purity and attained approximately 35 nm average crystallite size. The SEM images exposed that primary morphology nano-particles has been tuned into nanorods by increasing the La concentration in CeO2 with size range 40~60 nm. CV graphs depicted that the prepared electrodes obey the pseudo capacitive faradaic reactions behavior in nature. Maximum capacitance (925 F g-1) has been achieved by La0·05Ce0·95O2 which is better than numerous reported materials. The La0·05Ce0·95O2 also exhibited excellent GCD stability with 87.8% retention exhibiting it suitability for supercapacitor applications. Furthermore, the La0·05Ce0·95O2 showed the significantly higher H2 (9 μmol h?1g?1) production rate as compared to undoped CeO2 and La0·01Ce0·99O2, La0·03Ce0·97O2 samples. This higher production is attributed to the recombination rate and have strong substantial correlation with optical characteristics. 相似文献
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钙钛矿结构氧化物因其优异的MIEC特性和催化性能,以及具有化学组成的选择灵活性和良好的稳定性等优点,成为最有前途和应用前景的固体氧化物燃料电池(SOFC)阴极材料。目前,SOFC的发展趋势是中低温化。但是,随着电池操作温度的降低,阴极极化损耗急剧增加,电池性能随之下降。考虑到中低温SOFC对阴极材料的要求,钙钛矿型阴极的催化活性仍然较低。因此,钙钛矿型阴极的性能优化正在成为新的研究热点。文中综述了近年来钙钛矿阴极的性能优化研究的新进展,着重论述了元素掺杂、形貌调控以及浸渍改性等方式对钙钛矿阴极电化学性能的优化效果。 相似文献
5.
A cheap and commercially available small molecule (namely EPPDI) is introduced to the active layer of N2200-based all polymer solar cells as a solid additive. EPPDI at the optimal ratio can improve the D-A nano-scale morphology and reduce trap density of the active layer by filling morphological spaces. As a result, the photovoltaic performance of the resulting devices based on PF2:N2200 are increased from 6.28% to 7.03% with significantly enhanced fill factor. This work demonstrates a facile approach for improving the performance of all polymer solar cells. 相似文献
6.
城郊乡村的乡土景观面临"重写",而其间的乡土住宅正在经历一种自发的转型,其"自组织"的生成机制值得研究。本文以科尔沁右翼前旗地区的若干村镇的当代乡土住宅为样本,从组织机制的角度,分析其受控过程,分别从基因、共享、突变和蔓延四个方面展开分析,总结该地区的当代乡土住宅从无序向有序的演变过程。 相似文献
7.
《Ceramics International》2019,45(14):16803-16808
A feasible method has been developed for the morphology control of ordered supermicroporous silicas by adopting a kind of rosin-based surfactant as the templating agent. By adjusting the molar ratio of sodium silicate (SS) and ethyl acetate (EA), the morphologies of the materials can be changed from hollow sphere to hollow tube, and solid rod, while the degree of ordering of the samples showed a trend of firstly increasing and then decreasing. When the molar ratio of SS/EA was 0.38, an ordered supermicroporous silica with a hollow tubular morphology was obtained. The material had a surface area of 645.5 m2/g, a pore volume of 0.3 cm3/g, and a pore size distribution centered at 1.8 nm. When the molar ratio of SS/EA was increased to 0.46, the resulting sample exhibited a solid-rod morphology with a highly ordered hexagonal supermicroporous structure. This material had a large surface area of 1478.1 m2/g, a high pore volume of 0.7 cm3/g, and a uniform pore size distribution centered at 2.0 nm. 相似文献
8.
《International Journal of Hydrogen Energy》2019,44(4):2091-2127
“Superstructures” are basically three dimensional (3D) nano/microstructures which arise at the expense of one dimensional (1D) and two dimensional (2D) nanostructures with controlled morphology and orientation. As compared to 1D and 2D nanostructures ZnO superstructures are superior because they possess good crystallinity, integrated stacked arrays with periodic arrangement, high surface area, and good conductivity. Over the past few decades specific focus has been given on the synthesis of ZnO superstructures in view of their astonishing physicochemical properties and promising applications in numerous fields. ZnO superstructures show exceptional performance for hydrogen production via photoelectrochemical (PEC) water splitting because of their certain advantageous properties such as high internal surface area, enhanced scattering with improved light harvesting, reduced recombination rate, low charge transfer resistance, better crystallinity, channelled conducting pathways, etc. These properties are majorly dependent on the various morphologies of ZnO superstructures. Recently different synthesis strategies have been developed to obtain a variety of morphologies of ZnO superstructures. In view of the search for renewable energy sources in the form of hydrogen, produced through water splitting using PEC cell, it is crucial to study different recent approaches of synthesizing ZnO superstructures and understand their role in enhancing PEC performance. Herein, we recap the principles governing hierarchy, complexity, orientation and crystallinity of ZnO superstructures. In general, they are distinguished by considering their geometrical shapes and common names used in the literature and discussion is done on the strategies acquired for their synthesis. This review summarizes the reasons behind the exceptional performance of ZnO superstructures and discusses those in detail. In the field of ZnO superstructures synthesis and their applicability for hydrogen production through PEC this review will not only help in basic understanding, but also ignite innovative ideas. 相似文献
9.
使用Ti Al N涂层整体圆柱立铣刀,以(151~942)m/min的铣削速度,对淬硬的45钢和3Cr2Mo钢进行了高速铣削试验,研究了各种切削速度下的宏观及微观切屑形态。发现在高的铣削速度下形成了带有绝热剪切带的锯齿形切屑,并分析了切屑形态的演化过程。工件材料的硬度、强度、导热性能及切削速度对切屑形态和绝热剪切带的形成有着重要的影响。工件材料越硬、强度越高、导热系数越低,切削速度越大,越容易形成带有绝热剪切带的锯齿形切屑,而且,随着切削速度的增加,切屑的形态由卷曲向平坦发展。 相似文献
10.
Cuiping Wang Changrui Qiu Haiting Wei Hongwei Zou Kairui Lin Yihui Guo Shuiyuan Yang Xingjun Liu 《International Journal of Hydrogen Energy》2021,46(14):9314-9323
The development of mild hydrogen-generating materials is of great significance to improve the working life of hydrogen–oxygen fuel cells. In this study, Al–Bi–Zn composite powders were designed by phase diagram calculation and then prepared via the gas atomization method. The results indicated that the conversion yield of Al–12Bi–7Zn (wt.%) powder reached 98% with stable hydrogen production within 280 min at 50 °C. When composite powder reacted with NaCl solution to produce hydrogen, the dormant period of the reaction process was significantly shortened, but the conversion rate was slightly reduced. Additionally, the evolution of powder morphology during the reaction was investigated. The results showed that the continuous cracking of the powder led to the continuous exposure of fresh Al to react. 相似文献