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71.
Yuhan Wang Hua Jin Qiang Ma Kai Mo Haizhuo Mao Armin Feldhoff Xingzhong Cao Yanshuo Li Fusheng Pan Zhongyi Jiang 《Angewandte Chemie (International ed. in English)》2020,59(11):4365-4369
Metal–organic framework (MOF) glasses are promising candidates for membrane fabrication due to their significant porosity, the ease of processing, and most notably, the potential to eliminate the grain boundary that is unavoidable for polycrystalline MOF membranes. Herein, we developed a ZIF‐62 MOF glass membrane and exploited its intrinsic gas‐separation properties. The MOF glass membrane was fabricated by melt‐quenching treatment of an in situ solvothermally synthesized polycrystalline ZIF‐62 MOF membrane on a porous ceramic alumina support. The molten ZIF‐62 phase penetrated into the nanopores of the support and eliminated the formation of intercrystalline defects in the resultant glass membrane. The molecular sieving ability of the MOF membrane is remarkably enhanced via vitrification. The separation factors of the MOF glass membrane for H2/CH4, CO2/N2 and CO2/CH4 mixtures are 50.7, 34.5, and 36.6, respectively, far exceeding the Robeson upper bounds. 相似文献
72.
报道了一种用高价碘试剂促进缩氨基硫脲分子内氧化偶联反应,能够有效地合成2-氨基-1,3,4-噻二唑类衍生物.高价碘可以作为温和的反应试剂,拥有毒性低、廉价可循环易操作的特性.该反应具有原料易制得、操作简便以及较好的底物适用性等特点.反应机理也进行了初步研究. 相似文献
73.
Five isostructural tetranuclear lanthanide complexes with the general formula [Ln4(teaH2)2(teaH)2(NO3)6] · 2CH3OH [Ln3+ = Dy3+ ( 1 ), Tb3+ ( 2 ), Ho3+ ( 3 ), Er3+ ( 4 ), and Gd3+ ( 5 )] were successfully synthesized by the reaction of various lanthanide nitrate and triethanolamine (teaH3) ligand. Single crystal X-ray analyses reveal the eight-coordinate Ln3+ centers adopt a slightly distorted triangular dodecahedron geometry and nine-coordinate Ln3+ ions own an approximately capped square antiprism environment in similar zigzag Ln4 core. Magnetic studies demonstrate the presence of anitferromagnetic interactions between Ln3+ centers without obvious SMM behavior. 相似文献
74.
Yizhong Yuan Heng Liu Xuyang Li Wenqiang Qi Dujia Cheng Tao Tang Quanyu Zhao Wei Wei Yuhan Sun 《Applied biochemistry and biotechnology》2018,185(2):419-433
Accumulated carbohydrate in microalgae is promising feedstock for bioethanol fermentation. Selection of suitable cultivation conditions in semi-continuous cultivation is critical to achieve a high carbohydrate productivity. In the current study, the effects of macro-nutrient (nitrogen, phosphorus, and sulfur) limitations and light intensity were evaluated for the carbohydrate accumulations of Chlorella sp. AE10 under 10% CO2 conditions. It was shown that nitrogen limitation and high light intensity were effective for improving carbohydrate productivity. The average carbohydrate and biomass productivity in semi-continuous cultivation with 1/4 N medium and 1000 μmol photons m?2 s?1 was 0.673 and 0.93 g L?1 day?1, respectively. Sulfur and phosphorus limitations could improve the carbohydrate content but they could not enhance the carbohydrate productivity. The cell cycle progression and chlorophyll a were investigated using flow cytometry (FCM). The results showed that macro-nutrient limitation and high light intensity indeed influenced cell cycle progression and led to the formation of polyploid cells along with the carbohydrate accumulation in a certain range. FCM was rapid and accurate method to investigate the operation conditions why 1/4 N, 2 days as a cycle, and high light intensity were optimal ones. In addition, the remaining high level of photosynthesis activity was also important for achieving a high carbohydrate productivity. Dynamic tracking of carbohydrate accumulation is helpful for establishment of a semi-continuous cultivation for enhancing carbohydrate productivity in microalgae. 相似文献
75.
Meidi Wang Yutong Wang Junyi Zhao Jiyu Zou Xu Liang Ziting Zhu Jiashi Zhu Hongjian Wang Yuhan Wang Fusheng Pan Zhongyi Jiang 《Angewandte Chemie (International ed. in English)》2023,62(13):e202219084
Ultrathin covalent organic framework (COF) membranes are urgently demanded in molecular/ionic separations. Herein, we reported an electrochemical interfacial polymerization strategy to fabricate ultrathin COF membranes with thickness of 85 nm, by actively manipulate self-healing effect and self-inhibiting effect. The resulting COF membrane exhibited superior performance in brine desalination with the permeation flux of 92 kg m−2 h−1 and the rejection of 99.96 %. Our electrochemical interfacial polymerization strategy enriches the fabrication approach of COF membranes and facilitates the rational design of ultrathin membranes. 相似文献
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77.
Yuhan Xie Dr. Xin Chen Dr. Kaian Sun Dr. Jinqiang Zhang Dr. Wei-Hong Lai Prof. Hao Liu Prof. Guoxiu Wang 《Angewandte Chemie (International ed. in English)》2023,62(17):e202301833
The oxygen reduction reaction (ORR) on transition single-atom catalysts (SACs) is sustainable in energy-conversion devices. However, the atomically controllable fabrication of single-atom sites and the sluggish kinetics of ORR have remained challenging. Here, we accelerate the kinetics of acid ORR through a direct O−O cleavage pathway through using a bi-functional ligand-assisted strategy to pre-control the distance of hetero-metal atoms. Concretely, the as-synthesized Fe−Zn diatomic pairs on carbon substrates exhibited an outstanding ORR performance with the ultrahigh half-wave potential of 0.86 V vs. RHE in acid electrolyte. Experimental evidence and density functional theory calculations confirmed that the Fe−Zn diatomic pairs with a specific distance range of around 3 Å, which is the key to their ultrahigh activity, average the interaction between hetero-diatomic active sites and oxygen molecules. This work offers new insight into atomically controllable SACs synthesis and addresses the limitations of the ORR dissociative mechanism. 相似文献
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环境友好型半导体光催化是当前最具前景的光催化技术之一,它不仅能够将太阳能转化为化学能以解决能源危机,还可以将污染物降解矿化从而解决环境问题.但是,传统的半导体光催化剂受限于光利用率低、光生载流子复合率高、稳定性较差等几个方面,无法达到理想的光催化效果.在半导体光催化剂上负载助催化剂是提升光催化效率的有效策略之一.负载助催化剂能够增强光生电荷在半导体与助催化剂界面间的传输,提供额外的催化活性位点,增强光捕获能力,因而被广泛应用于光催化剂的改性.目前广泛使用的贵金属助催化剂包括Au,Ag,Pt,Ru等,虽然这些贵金属助催化剂性能优异,但是它们存在储量少和成本高的问题,严重影响其规模化应用.因此,开展高效且成本低廉的非贵金属助催化剂的研究非常必要.近来,一种新型二维过渡金属材料(MXene)因其具有独特的二维层状结构、优异的导电性能、出色的光学和热力学性质而成为催化领域的研究热点.本文综述了有关非贵金属助催化剂MXene在光催化领域的最新研究进展,内容包括:(1)MXene材料的体相与表面结构特性;(2)薄层MXene的制备方法,例如氢氟酸刻蚀法、氢氟酸替代物刻蚀法以及熔融氟盐刻蚀法;(3)MXene基复合光催化剂的合成及改性策略,包括机械混合、自组装、原位氧化等;(4)MXene辅助增强光催化活性机理.论文还重点介绍了MXene作为助催化剂在光催化领域中的应用,包括光催化分解水产氢、光催化CO2还原、光催化固氮以及有机污染物的光催化降解.最后,论文分析了MXene基异质结光催化剂存在的问题与面临的挑战,并对MXene助催化剂的未来发展进行了展望.主要观点包括:(1)关于光催化分解水、空气净化、合成氨领域的研究较少,需要进一步开展;(2)MXene基异质结光催化剂的反应机理仍存在争议,需采用现代化仪器设备(包括原位表征技术)对其进行更为深入的探究;(3)目前,大多数MXene材料的制备都是通过强腐蚀性的氢氟酸或氢氟酸替代物刻蚀,开发环境友好且高效的MXene制备方法迫在眉睫;(4)阐明MXene表面终端基团的作用有助于提升MXene基复合光催化剂的性能;(5)引入新的改性策略如局域表面等离子体共振效应(LSPR)、缺陷调控、单原子催化(SAC)等来提高MXene基光催化剂的催化性能,是未来MXene基复合催化剂的发展方向. 相似文献