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991.
Peng Zhang Xue Feng Lu Deyan Luan Xiong Wen Lou 《Angewandte Chemie (International ed. in English)》2020,59(21):8128-8132
Photocatalysts with well‐designed compositions and structures are desirable for achieving highly efficient solar‐to‐chemical energy conversion. Heterostructured semiconductor photocatalysts with advanced hollow structures possess beneficial features for promoting the activity towards photocatalytic reactions. Here we develop a facile synthetic strategy for the fabrication of Fe2TiO5–TiO2 nanocages (NCs) as anode materials in photoelectrochemical (PEC) water splitting cells. A hydrothermal reaction is performed to transform MIL‐125(Ti) nanodisks (NDs) to Ti–Fe–O NCs, which are further converted to Fe2TiO5–TiO2 NCs through a post annealing process. Owing to the compositional and structural advantages, the heterostructured Fe2TiO5–TiO2 NCs show enhanced performance for PEC water oxidation compared with TiO2 NDs, Fe2TiO5 nanoparticles (NPs) and Fe2TiO5–TiO2 NPs. 相似文献
992.
Chao Wang Min Hu Yueying Chu Xue Zhou Qiang Wang Guodong Qi Shenhui Li Jun Xu Feng Deng 《Angewandte Chemie (International ed. in English)》2020,59(18):7198-7202
The understanding of catalyst deactivation represents one of the major challenges for the methanol‐to‐hydrocarbon (MTH) reaction over acidic zeolites. Here we report the critical role of intermolecular π‐interactions in catalyst deactivation in the MTH reaction on zeolites H‐SSZ‐13 and H‐ZSM‐5. π‐interaction‐induced spatial proximities between cyclopentenyl cations and aromatics in the confined channels and/or cages of zeolites are revealed by two‐dimensional solid‐state NMR spectroscopy. The formation of naphtalene as a precursor to coke species is favored due to the reaction of aromatics with the nearby cyclopentenyl cations and correlates with both acid density and zeolite topology. 相似文献
993.
Min Bai Feng Chen Xiaowen Cao Yue Zhao Jing Xue Xu Yu Chunhai Fan Yongxi Zhao 《Angewandte Chemie (International ed. in English)》2020,59(32):13267-13272
Tumor progressions such as metastasis are complicated events that involve abnormal expression of different miRNAs and enzymes. Monitoring these biomolecules in live cells with computational DNA nanotechnology may enable discrimination of tumor progression via digital outputs. Herein, we report intracellular entropy‐driven multivalent DNA circuits to implement multi‐bit computing for simultaneous analysis of intracellular telomerase and microRNAs including miR‐21 and miR‐31. These three biomolecules can trigger respective DNA strand displacement recycling reactions for signal amplification. They are visualized by fluorescence imaging, and their signal outputs are encoded as multi‐bit binary codes for different cell types. The results can discriminate non‐tumorigenic, malignant and metastatic breast cells as well as respective tumors. This DNA computing circuit is further performed in a microfluidic chip to differentiate rare co‐cultured cells, which holds a potential for the analysis of clinical samples. 相似文献
994.
Shijia Feng Tuo Wang Bin Liu Congling Hu Lulu Li Zhi‐Jian Zhao Jinlong Gong 《Angewandte Chemie (International ed. in English)》2020,59(5):2044-2048
A facile photoetching approach is described that alleviates the negative effects from bulk defects by confining the oxygen vacancy (Ovac) at the surface of BiVO4 photoanode, by 10‐minute photoetching. This strategy could induce enriched Ovac at the surface of BiVO4, which avoids the formation of excessive bulk defects. A mechanism is proposed to explain the enhanced charge separation at the BiVO4 /electrolyte interface, which is supported by density functional theory (DFT) calculations. The optimized BiVO4 with enriched surface Ovac presents the highest photocurrent among undoped BiVO4 photoanodes. Upon loading FeOOH/NiOOH cocatalysts, photoetched BiVO4 photoanode reaches a considerable water oxidation photocurrent of 3.0 mA cm?2 at 0.6 V vs. reversible hydrogen electrode. An unbiased solar‐to‐hydrogen conversion efficiency of 3.5 % is realized by this BiVO4 photoanode and a Si photocathode under 1 sun illumination. 相似文献
995.
Nanofiltration (NF) membranes have been widely used for the treatment of electroplating, aerospace, textile, pharmaceutical, and other chemical industries. In this work, halloysite nanotubes (HNTs) were directly anchored on the surface of commercial nanofiltration (NF) membrane by dopamine modification following advantageous bio‐inspired methods. SEM and AFM images were used to characterize the HNTs decorated membrane surface in terms of surface morphology and roughness. Water contact angle (WCA) was employed in evidencing the incorporation of HNTs and dopamine in terms of hydrophilicity or hydrophobicity. Augmentation of HNTs was found to obviously enhance the hydrophilicity and surface roughness resulting in improved water permeability of membrane. More importantly, the rejection ratios of membrane also increased during the removal of heavy metal ions from wastewater. The permeability and Cu2+ rejection ratio of modified NF membrane were as high as 13.9 L·m?2·h?1·bar?1 and 74.3%, respectively. Incorporation of HNTs was also found to enhance the anti‐fouling property and stability of membrane as evident from long‐term performance tests. The relative concentration of HNTs and dopamine on membrane surface was optimized by investigating the trade‐off between water permeability and rejection ratio. 相似文献
996.
Du Junping Feng Shanshan Qin Pengju Zhang Yonghui Zhang Zhiqiang Xu Liancai 《Structural chemistry》2020,31(5):1785-1792
Structural Chemistry - A series of strontium para-tetraphenyl porphyrins (SrTRPPs) with different electron property substituents (R?=?-NH2, -OCH3, -H, -F, -COOH, -NO2) on the... 相似文献
997.
Hydrogen stable isotope analysis has been a valuable tool in the fields of geochemistry and ecological research as well as many other research fields. The methods are mainly divided into the dual‐inlet method (off‐line method) and continuous flow method. The dual‐inlet method is complicated and inefficient, but it is still important because of its high precision and wide application range. Although the continuous flow method improves the experimental efficiency, the memory effect is noticeable and the accuracy is reduced. An improved sealed quartz‐tube method is proposed in this paper. The sample is sealed in a capillary tube and placed in a quartz tube containing chromium powder. It is then packaged, evacuated, reacted at a high temperature, and analyzed for hydrogen isotope ratio. Excellent data accuracy, good reproducibility (<1‰), and no memory effect occurred in the method. The process is relatively simple, and the experimental efficiency is greatly improved, which provides an effective method for the analysis of hydrogen isotopes in complex liquid samples. 相似文献
998.
999.
Tomohiro Seki Chi Feng Kentaro Kashiyama Shunichi Sakamoto Yuichi Takasaki Toshiyuki Sasaki Satoshi Takamizawa Hajime Ito 《Angewandte Chemie (International ed. in English)》2020,59(23):8839-8843
Ferroelasticity has been reported for several types of molecular crystals, which show mechanical‐stress‐induced shape change under twinning and/or spontaneous formation of strain. Aiming to create materials that exhibit both ferroelasticity and light‐emission characteristics, we discovered the first examples of ferroelastic luminescent organometallic crystals. Crystals of arylgold(I)(N‐heterocyclic carbene)(NHC) complexes bend upon exposure to anisotropic mechanical stress. X‐ray diffraction analyses and stress‐strain measurements on these ferroelastic crystals confirmed typical ferroelastic behavior, mechanical twinning, and the spontaneous build‐up of strain. A comparison with single‐crystal structures of related gold‐NHC complexes that do not show ferroelasticity shed light on the structural origins of the ferroelastic behavior. 相似文献
1000.
Jing Qi Feng‐Lian Zhang Ji‐Kang Jin Qiang Zhao Bin Li Lin‐Xuan Liu Yi‐Feng Wang 《Angewandte Chemie (International ed. in English)》2020,59(31):12876-12884
Radical borylation using N‐heterocyclic carbene (NHC)‐BH3 complexes as boryl radical precursors has emerged as an important synthetic tool for organoboron assembly. However, the majority of reported methods are limited to reaction modes involving carbo‐ and/or hydroboration of specific alkenes and alkynes. Moreover, the generation of NHC‐boryl radicals relies principally on hydrogen atom abstraction with the aid of radical initiators. A distinct radical generation method is reported, as well as the reaction pathways of NHC‐boryl radicals enabled by photoredox catalysis. NHC‐boryl radicals are generated via a single‐electron oxidation and subsequently undergo cross‐coupling with the in‐situ‐generated radical anions to yield gem‐difluoroallylboronates. A photoredox‐catalyzed radical arylboration reaction of alkenes was achieved using cyanoarenes as arylating components from which elaborated organoborons were accessed. Mechanistic studies verified the oxidative formation of NHC‐boryl radicals through a single‐electron‐transfer pathway. 相似文献