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961.
962.
Jingyi Cai Haoshan Wei Prof. Yong Zhang Rui Cai Dr. Xueru Zhang Prof. Yan Wang Prof. Jiaqin Liu Prof. Hark Hoe Tan Prof. Ting Xie Prof. Yucheng Wu 《Chemistry (Weinheim an der Bergstrasse, Germany)》2021,27(25):7300-7306
Efficient separation of photogenerated electron–hole pairs is a crucial factor for high-performance photocatalysts. Effective electron–hole separation and migration could be achieved by heterojunctions with suitable band structures. Herein, a porous SrTiO3/SrSO4 heterojunction is prepared by a sol-gel method at room temperature followed by an annealing process. XRD characterization suggests high crystallinity of the heterostructure. A well-defined interface between the two phases is confirmed by high-resolution (HR)TEM. The photocatalytic H2 evolution productivity of the SrTiO3/SrSO4 heterojunction with Pt as co-catalyst reaches 396.82 μmol g−1 h−1, which is 16 times higher than that of SrTiO3/Pt. The boosted photocatalytic activity of SrTiO3/SrSO4/Pt can be ascribed to the presence of SrSO4, which promotes the transfer and migration of photogenerated carriers by forming the heterojunction and porous structure, which provides a large amount of active sites. This novel porous heterostructure brings new ideas for the development of high-efficiency photocatalysts for H2 release. 相似文献
963.
Chia-Wen Lu Yan Cao Hui Li Cathleen Webb Wei-Ping Pan 《Journal of Thermal Analysis and Calorimetry》2014,116(3):1241-1248
Titanium dioxide (TiO2), especially in its anatase form, is an effective photocatalyst under ultraviolet (UV) light. The particle size of TiO2 is a critical factor to determine its photoactivity based on its quantum effectiveness under light irradiations. Thus, nanocrystalline TiO2 has been widely accepted to significantly enhance this effect. The sol–gel method is generally used to synthesize the anatase form of nanocrystalline TiO2. In this study, we expanded the synthesis method of TiO2 to high pressures under direct heating (hydrothermal method) and indirect heating (microwave-assisted method). It was found that pH value is one of the major factors to control nano-sizes of TiO2 particles, and the neutral condition in all methods is preferable for controlling the sizes of the prepared TiO2 particles. The microwave-assisted method further improves quality of synthesized nano-size TiO2 below 10 nm. These results have been confirmed by both the direct size measurement using TEM images and indirect determination using XRD peaks. The collected samples are further analyzed using UV–Vis spectroscopy to identify the particle size-dependent photoreactivity and to confirm the effectiveness of microwave-assisting under neutral conditions. DSC is also a powerful tool to identify the crystalline transition of TiO2. 相似文献
964.
Hang Ma Yang He Ruo-Feng Huang Xiao-Hui Zhang Jing Pan Jia-Qiang Li Chao He Xue-Ge Ling Xuan-Lun Wang Yan Xiong 《中国化学快报》2014,25(10):1327-1330
Under neat conditions,an efficient method for synthesis of imidoesters has been developed using cyanatobenzenes and dicarbonyl compounds.Nucleophilic addition spontaneously occurred between the two kinds of materials at room temperature with yields of up to 90%.A mechanism directed towards to the imidoester formation has been proposed. 相似文献
965.
966.
967.
968.
Dr. Chun-Xiao Li Qian Ning Wenxuan Zhao Hou-Ji Cao Yi-Ping Wang Prof. Dr. Hong Yan Prof. Dr. Chang-Sheng Lu Prof. Dr. Yong Liang 《Chemistry (Weinheim an der Bergstrasse, Germany)》2021,27(8):2699-2706
The convenient cross-coupling of sp2 or sp3 carbons with a specific boron vertex on carborane cage represents significant synthetic values and insurmountable challenges. In this work, we report an Rh-catalyzed reaction between o-carborane and N-acyl-glutarimides to construct various Bcage−C bonds. Under the optimized condition, the removable imine directing group (DG) leads to B(3)− or B(3,6)−C couplings, while the pyridyl DG leads to B(3,5)−Ar coupling. In particular, an unexpected rearrangement of amide reagent is observed in pyridyl directed B(4)−C(sp3) formation. This scalable protocol has many advantages, including easy access, the use of cheap and widely available coupling agents, no requirement of an external ligand, base or oxidant, high efficiency, and a broad substrate scope. Leveraging the RhI dimer and twisted amides, this method enables straightforward access to diversely substituted and therapeutically important carborane derivatives at boron site, and provides a highly valuable vista for carborane-based drug screening. 相似文献
969.
970.
Li Zhu Kun Liu Shudong Zheng Dr. Xiacong Zhang Prof. Dr. Jiatao Yan Prof. Dr. Wen Li Prof. Dr. Afang Zhang 《Chemistry (Weinheim an der Bergstrasse, Germany)》2021,27(40):10470-10476
Water-soluble and thermoresponsive macrocycles with stable inclusion toward guests are highly valuable to construct stimuli-responsive supramolecular materials for versatile applications. Here, we develop such macrocycles – ureido-substituted cyclodextrins (CDs) which exhibit unprecedented upper critical solution temperature (UCST) behavior in aqueous media. These novel CD derivatives showed good solubility in water at elevated temperature, but collapsed from water to form large coacervates upon cooling to low temperature. Their cloud points are greatly dependent on concentration and can be mediated through oxidation and chelation with silver ions. Significantly, the amphiphilicity of these CD derivatives is supportive to host-guest binding, which affords them inclusion abilities to guest dyes. The inclusion complexation remained nearly intact during thermally induced phase transitions, which is in contrast to the switchable inclusion behavior of lower critical solution temperature (LCST)-type CDs. Moreover, ureido-substituted CDs were exploited to co-encapsulate a pair of guest dyes whose fluorescence resonance energy transfer process can be switched by the UCST phase transition. We therefore believe these novel thermoresponsive CDs may form a new strategy for developing smart macrocycles and allow for exploring smart supramolecular materials. 相似文献