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61.
Xinyi Yang Dr. Yajun He Prof. Liuyi Li Dr. Jinni Shen Prof. Jianhui Huang Prof. Lingyun Li Prof. Zanyong Zhuang Prof. Jinhong Bi Prof. Yan Yu 《Chemistry (Weinheim an der Bergstrasse, Germany)》2020,26(8):1864-1870
Facile fabrication of nanocatalysts consisting of metal nanoparticles (NPs) anchored on a functional support is highly desirable, yet remains challenging. Covalent organic frameworks (COFs) provide an emerging materials platform for structural control and functional design. Here, a facile one-pot in situ reduction approach is demonstrated for the encapsulation of small Pd NPs into the shell of COF-derived hollow polyamine spheres (Pd@H-PPA). In the one-pot synthetic process, the nucleation and growth of Pd NPs in the cavities of the porous shell take place simultaneously with the reduction of imine linkages to secondary amine groups. Pd@H-PPA shows a significantly enhanced catalytic activity and recyclability in the tandem dehydrogenation of ammonia borane and selective hydrogenation of nitroarenes through an adsorption–activation–reaction mechanism. The strong interactions of the secondary amine linkage with borane and nitroarene molecules afford a positive synergy to promote the catalytic reaction. Moreover, the hierarchical structure of Pd@H-PPA allows the accessibility of active Pd NPs to reactants. 相似文献
62.
CO2 electrocatalysis as a hydrocarbon is a promising means of achieving economical CO2-mediated hydrogen energy cycling. Hydrocarbons are renewable hydrogen storage materials. The development of reliable metal alloy electrocatalysts is an urgent but challenging task associated with such systems, although there is still a lack of precise reaction mechanism design. In this study, the performance of Pd10Ag5 alloy nanoparticles (NPs) and Pd10Sn5 alloy nanoparticles (NPs) on the electrocatalytic reaction of CO2 was compare. The kinetic and density functional theory (DFT) calculations show that the selectivity of the Pd-based bimetallic catalyst to the C2 product is greater than that of C1, and the stability of Pd10Ag5 is better and less affected by the reaction environment. However, the catalytic performance of the Pd10Sn5 electrocatalyst in the liquid phase is the best. The insight obtained from the calculations is used to develop criteria for identifying new and improved catalysts for electrochemical CO2 reduction. 相似文献
63.
聚氨酯/聚(苯乙烯—甲基丙烯酸甲酯—甲基丙烯酸互穿聚合物网络的研究 总被引:2,自引:0,他引:2
研究了聚氨酯/聚互穿合笺网络,动态力学性能及透射电镜结果均表明该体系相分离较严重。INP具有两个玻璃化转变温度,它们有不同程度的内移,形成一定程度分子水平的混合。而IPN(50/50)其分子混合水平较大,互穿缠结程度较高。 相似文献
64.
聚丙烯酸酯/聚苯乙烯乳胶互穿聚合物网络阻尼性能的研究 总被引:14,自引:0,他引:14
聚丙烯酸酯/聚苯乙烯乳胶互穿聚合物网络阻尼性能的研究刘瑞瑛王静媛韩庆国李玉玮汤心颐(吉林大学化学系长春130023)关键词互穿聚合物网络,聚丙烯酸酯,聚苯乙烯,阻尼性能,乳胶自1969年Sperling和Frisch分别发展了MilarIPN的... 相似文献
65.
66.
Yixuan Wang Hao Liu Min Wu Kai Wang Yongming Sui Zhaodong Liu Siyu Lu Zhihong Nie John S. Tse Xinyi Yang Bo Zou 《Chemical science》2021,12(19):6580
Core/shell nanocrystals (NCs) integrate collaborative functionalization that would trigger advanced properties, such as high energy conversion efficiency, nonblinking emission, and spin–orbit coupling. Such prospects are highly correlated with the crystal structure of individual constituents. However, it is challenging to achieve novel phases in core/shell NCs, generally non-existing in bulk counterparts. Here, we present a fast and clean high-pressure approach to fabricate heterostructured core/shell MnSe/MnS NCs with a new phase that does not occur in their bulk counterparts. We determine the new phase as an orthorhombic MnP structure (B31 phase), with close-packed zigzagged arrangements within unit cells. Encapsulation of the solid MnSe nanorod with an MnS shell allows us to identify two separate phase transitions with recognizable diffraction patterns under high pressure, where the heterointerface effect regulates the wurtzite → rocksalt → B31 phase transitions of the core. First-principles calculations indicate that the B31 phase is thermodynamically stable under high pressure and can survive under ambient conditions owing to the synergistic effect of subtle enthalpy differences and large surface energy in nanomaterials. The ability to retain the new phase may open up the opportunity for future manipulation of electronic and magnetic properties in heterostructured nanostructures.Core/shell MnSe/MnS nanocrystals with the B31 phase are thermodynamically stable under high pressure and can survive under ambient conditions owing to the synergistic effect of subtle enthalpy differences and high surface energy in nanomaterials. 相似文献
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68.
微量量热法研究液固吸附正逐渐引起人们的兴趣。本实验室拟开展强化采油中表面活性剂在固体表面吸附机理的研究,装配了一台微量吸附热量计,并用标准化学反应检测其可靠性。研究表面活性剂的吸附规律,需要选用合适的吸附剂。硅胶的组份简单确定,不含干扰离子,表面积足够大,而且它就是油井矿物、粘土等的主要成份,被选为吸附剂样品。但硅胶的表面状态易受制备过程、热处理等因素影响,迄今尚无统一标准的硅胶表面,使用时应表征其表面状态。本文用热失重分析确定硅胶的活化温度、用微量吸附热量计测量了硅胶的浸湿热,并与文献数据进行比较。 相似文献
69.
运用TP-FT-IR技术研究了CO、NO、NO+CO在负载型Cu-Fe-Ce-O(Ⅰ)和Cu-Fe-O(Ⅱ)催化剂上的吸附行为。研究表明,NO具有比CO更强的吸附能力,可与表面氧反应生成硝基、亚硝酸盐、硝酸盐等物种.在NO+CO反应过程中,在催化剂表面存在(CO.NO)*表面络合物(2400—2430cm ̄(-1))和NCO*(异氰酸盐)表面物种,其关系为:CO*+NO*→(CO.NO)*+*→NCO*+O*.在(Ⅱ)中加入铈,能提高CO在表面的吸附强度,使NCO*的稳定性下降,同时对NO在表面的吸附产生影响。根据研究的结果,提出了NO+CO在模型催化剂上的表面反应机理. 相似文献
70.
Wei Wang Hongxia Xu Elizabeth R. Rayburn Xu Zhang Evrim Gurpinar Xinyi Yang Charnell I. Sommers Sadanandan E. Velu Ruiwen Zhang 《Biomedical chromatography : BMC》2011,25(5):628-634
We herein describe the development and validation of an HPLC method for the quantitation of 7‐(benzylamino)‐1,3,4,8‐tetrahydropyrrolo [4,3,2‐de]quinolin‐8(1H)‐one (BA‐TPQ), a newly synthesized iminoquinone anticancer agent. BA‐TPQ was extracted from plasma and tissue samples by first precipitating proteins with acetonitrile followed by a liquid–liquid extraction with ethyl acetate. Chromatographic separation was carried out using a gradient flow rate on a Zorbax SB C18 column, and the effluent was monitored by UV detection at 346 nm. The method was found to be precise, accurate, and specific, with a linear range of 3.91–1955.0 ng/mL in plasma, 19.55–1955.0 ng/mL in spleen, brain, and liver homogenates and 19.55–3910.0 ng/mL in heart, lung and kidney homogenates. The method was stable under all relevant conditions. Using this method, we also carried out an initial study determining plasma pharmacokinetics and tissue distribution of BA‐TPQ in mice following intravenous administration. In summary, this simple and sensitive HPLC method can be used in future preclinical and clinical studies of BA‐TPQ. 相似文献