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981.
采用溶剂热法和溶胶-凝胶法制备了顺磁性Fe3O4@SiO2颗粒,以Pickering乳液界面保护法实现颗粒表面分区获得Fe3O4@SiO2 Janus颗粒,进一步选区复合生长Pt或Ag纳米颗粒制备Fe3O4@SiO2-Pt和Fe3O4@SiO2-Ag Janus颗粒.Fe3O4@SiO2-Pt Janus颗粒的Pt一侧进行催化过氧化氢的反应,具有自驱动功能.因其顺磁性和两亲性,Fe3O4@SiO2-Ag Janus颗粒能够作为磁响应颗粒乳化剂稳定油水乳液,并将Ag的催化功能引入界面. 相似文献
982.
An N‐heterocyclic carbene/nickel‐catalyzed direct coupling of alcohols and internal alkynes to form α‐branched ketones has been developed. This methodology provides a new approach to afford branched ketones, which are difficult to access through the hydroacylation of simple internal alkenes with aldehydes. This redox‐neutral and redox‐economical coupling is free from any oxidative or reductive additives as well as stoichiometric byproducts. These reactions convert both benzylic and aliphatic alcohols and alkynes, two basic feedstock chemicals, into various α‐branched ketones in a single chemical step. 相似文献
983.
Xuan Xie Shihan Qi Daxiong Wu Huaping Wang Fang Li Xiaoxin Peng Jinfeng Cai Jiaojiao Liang Jianmin Ma 《中国化学快报》2020,31(1):223-226
Hard carbon is promising anode for potassium-ion batteries(PIBs),however,the poor rate capability hinders its development as potential anode.To address this question,we design a sulfur-doped porous hard carbon(S-HC)for PIBs through the combination of structural design and composition adjustment.The as-designed S-HC exhibits a long cycling life with^191 mAh/g after 300 cycles at 1 A/g,and an excellent rate capability with^100 mAh/g at 5 A/g,which was attributed to its structural characteristics and compositions.The S-HC demonstrates to be promising anode in the future. 相似文献
984.
Yunwen Tao Zheng Pei Nicole Bellonzi Yuezhi Mao Zhu Zou Wanzhen Liang Zhibo Yang Yihan Shao 《International journal of quantum chemistry》2020,120(6):e26123
In the modeling of spin-crossing reactions, it has become popular to directly explore the spin-adiabatic surfaces. Specifically, through constructing spin-adiabatic states from a two-state Hamiltonian (with spin-orbit coupling matrix elements) at each geometry, one can readily employ advanced geometry optimization algorithms to acquire a “transition state” structure, where the spin crossing occurs. In this work, we report the implementation of a fully-variational spin-adiabatic approach based on Kohn-Sham density functional theory spin states (sharing the same set of molecular orbitals) and the Breit-Pauli one-electron spin-orbit operator. For three model spin-crossing reactions (predissociation of N2O, singlet-triplet conversion in CH2, and CO addition to Fe(CO)4), the spin-crossing points were obtained. Our results also indicated the Breit-Pauli one-electron spin-orbit coupling can vary significantly along the reaction pathway on the spin-adiabatic energy surface. On the other hand, due to the restriction that low-spin and high-spin states share the same set of molecular orbitals, the acquired spin-adiabatic energy surface shows a cusp (ie, a first-order discontinuity) at the crossing point, which prevents the use of standard geometry optimization algorithms to pinpoint the crossing point. An extension with this restriction removed is being developed to achieve the smoothness of spin-adiabatic surfaces. 相似文献
985.
Hao Zhang Wei Xia Haoming Shen Wenhan Guo Zibin Liang Kexin Zhang Yingxiao Wu Bingjun Zhu Ruqiang Zou 《Angewandte Chemie (International ed. in English)》2020,59(5):1871-1877
Antiperovskite Co3InC0.7N0.3 nanomaterials with highly enhanced oxygen reduction reaction (ORR) performance were prepared by tuning nitrogen contents through a metal–organic framework (MOF)‐derived strategy. The nanomaterial surpasses all reported noble‐metal‐free antiperovskites and even most perovskites in terms of onset potential (0.957 V at J=0.1 mA cm?2) and half‐wave potential (0.854 V). The OER and zinc–air battery performance demonstrate its multifunctional oxygen catalytic activities. DFT calculation was performed and for the first time, a 4 e? dissociative ORR pathway on (200) facets of antiperovskite was revealed. Free energy studies showed that nitrogen substitution could strengthen the OH desorption as well as hydrogenation that accounts for the enhanced ORR performance. This work expands the scope for material design via tailoring the nitrogen contents for optimal reaction free energy and hence performance of the antiperovskite system. 相似文献
986.
Liangliang Liang Wei Yan Xian Qin Xiao Peng Han Feng Yu Wang Ziyu Zhu Lingmei Liu Yu Han Qinghua Xu Junle Qu Xiaogang Liu 《Angewandte Chemie (International ed. in English)》2020,59(2):746-751
Stimulated emission depletion (STED) microscopy enables ultrastructural imaging of biological samples with high spatiotemporal resolution. STED nanoprobes based on fluorescent organosilica nanohybrids featuring sub‐2 nm size and near‐unity quantum yield are presented. The spin–orbit coupling (SOC) of heavy‐atom‐rich organic fluorophores is mitigated through a silane‐molecule‐mediated condensation/dehalogenation process, resulting in bright fluorescent organosilica nanohybrids with multiple emitters in one hybrid nanodot. When harnessed as STED nanoprobes, these fluorescent nanohybrids show intense photoluminescence, high biocompatibility, and long‐term photostability. Taking advantage of the low‐power excitation (0.5 μW), prolonged singlet‐state lifetime, and negligible depletion‐induced re‐excitation, these STED nanohybrids present high depletion efficiency (>96 %), extremely low saturation intensity (0.54 mW, ca. 0.188 MW cm?2), and ultra‐high lateral resolution (ca. λem/28). 相似文献
987.
Bentian Zhang Gengtao Fu Yutao Li Lecheng Liang Nicholas S. Grundish Yawen Tang John B. Goodenough Zhiming Cui 《Angewandte Chemie (International ed. in English)》2020,59(20):7857-7863
Controllable synthesis of atomically ordered intermetallic nanoparticles (NPs) is crucial to obtain superior electrocatalytic performance for fuel cell reactions, but still remains arduous. Herein, we demonstrate a novel and general hydrogel‐freeze drying strategy for the synthesis of reduced graphene oxide (rGO) supported Pt3M (M=Mn, Cr, Fe, Co, etc.) intermetallic NPs (Pt3M/rGO‐HF) with ultrasmall particle size (about 3 nm) and dramatic monodispersity. The formation of hydrogel prevents the aggregation of graphene oxide and significantly promotes their excellent dispersion, while a freeze‐drying can retain the hydrogel derived three‐dimensionally (3D) porous structure and immobilize the metal precursors with defined atomic ratio on GO support during solvent sublimation, which is not afforded by traditional oven drying. The subsequent annealing process produces rGO supported ultrasmall ordered Pt3M intermetallic NPs (≈3 nm) due to confinement effect of 3D porous structure. Such Pt3M intermetallic NPs exhibit the smallest particle size among the reported ordered Pt‐based intermetallic catalysts. A detailed study of the synthesis of ordered intermetallic Pt3Mn/rGO catalyst is provided as an example of a generally applicable method. This study provides an economical and scalable route for the controlled synthesis of Pt‐based intermetallic catalysts, which can pave a way for the commercialization of fuel cell technologies. 相似文献
988.
Russian Journal of Organic Chemistry - A mild and efficient B(C6F5)3-catalyzed conjugate addition of N, N-dialkylanilines to aromatic nitroalkenes is reported. The catalyst shows excellent... 相似文献
989.
Liu Zhimeng Jiang Liang Fu Xiaowei Zhang Junhua Lei Jingxin 《Journal of Thermal Analysis and Calorimetry》2020,140(5):2159-2170
Journal of Thermal Analysis and Calorimetry - In this study, a series of gelators (Gn, n is the number of carbon atoms of used fatty alcohol, n?=?2, 4, 6, 8, 10, 12, 14, 16 and 18) were... 相似文献
990.
Jiang Liang Lei Yuan Liu Qinfeng Wang Yi Zhao Yuanyang Lei Jingxin 《Journal of Thermal Analysis and Calorimetry》2020,139(1):137-146
Journal of Thermal Analysis and Calorimetry - The polyethylene glycol/wood-flour (PEG/WF) composites were synthesized as novel form-stable phase change materials (PCMs) using PEG as phase change... 相似文献