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941.
942.
由于全球的工农业的迅速发展,水污染已成为人类所面临的最大危机。基于半导体光催化法是治理水污染的绿色技术之一,能够有效地降解和去除水中的污染物。在众多光催化材料中,金属氧化物半导体由于其具有低毒性、高稳定性和对水溶液中化学腐蚀的较高的抵抗力等优点,而被科学家们广泛地研究和应用。其中,三元组分的金属氧化物因其具有较窄的禁带宽度和可见光响应性质,在光催化降解领域上的能力已经超过其他的金属化合物。本文系统地介绍了两种典型的三元金属氧化物——钨酸铋和钼酸铋,围绕着基于钨酸铋和钼酸铋的复合型催化剂的制备和在光催化降解废水处理领域中的应用以及发展进行了综述,提出了目前关于钨酸铋和钼酸铋的复合材料的设计、机理研究和改性修饰方法中的所存在的主要问题,并对未来的发展趋势进行了展望。 相似文献
943.
Wu Wen Shengsheng Yu Chaoqun Zhou Prof. Hao Ma Prof. Zhongyue Zhou Chuangchuang Cao Dr. Jiuzhong Yang Minggao Xu Prof. Fei Qi Prof. Guobin Zhang Prof. Yang Pan 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(12):4903-4908
HCHO has been confirmed as an active intermediate in the methanol-to-hydrocarbon (MTH) reaction, and is critical for interpreting the mechanisms of coke formation. Here, HCHO was detected and quantified during the MTH process over HSAPO-34 and HZSM-5 by in situ synchrotron radiation photoionization mass spectrometry. Compared with conventional methods, excellent time-resolved profiles were obtained to study the formation and fate of HCHO, and other products during the induction, steady-state reaction, and deactivation periods. Similar formation trends of HCHO and methane, and their close correlation in yields suggest that they are derived from disproportionation of methanol at acidic sites. In the presence of Y2O3, the amount of HCHO changes, affecting the hydrogen-transfer processes of olefins into aromatics and aromatics into cokes. The yield of HCHO affects the aromatic-based cycle and the formation of ethylene, indicating that ethylene is mainly formed from the aromatic-based cycle. 相似文献
944.
Yi-Fan Wang Yiyu Liang Yan-Fang Wu Jian Yang Xu Zhang Dr. Dandan Cai Dr. Xu Peng Dr. Mohamedally Kurmoo Prof. Dr. Ming-Hua Zeng 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(32):13334-13339
The in situ tracking of the pyrolysis of a binary molecular cluster [Zn7(μ3-CH3O)6(L)6][ZnLCl2]2 is presented with one brucite disk and two mononuclear fragments (L=mmimp: 2-methoxy-6-((methylimino)-methyl)phenolate) to porous carbon using TG-MS from 30 to 900 °C. Following up the spilled gas product during the decomposed reaction of zinc cluster along the temperature rising, and in conjunction with XRD, SEM, BET and other materials characterization, where three key steps were observed: 1) cleavage of the bulky external ligand; 2) reduction of ZnO and 3) volatilization of Zn. The real-time-dependent phase-sequential evolution of the remaining products and the processing of pore forming template transformation are proposed simultaneously. The porous carbon structure featuring a uniform nano-sized pore distribution synthesized at 900 °C with the highest surface area of 1644 m2 g−1 and pore volume of 0.926 cm3 g−1 exhibits the best known capacitance of 662 F g−1 at 0.5 A g−1. 相似文献
945.
946.
Yang Zheng Yao Li Lulu Huang Hexin Nan 《Journal of Dispersion Science and Technology》2019,40(6):918-924
A simple method for fabricating a metal organic framework (MOF: HKUST-1) as sorbent for selective removal of chromium (III) from aqueous solution is discussed. The structure and morphology of HKUST-1 was identified by fourier transform infrared (FT-IR) spectroscopy, scanning electron microscopy (SEM), the powder X-ray diffraction (XRD) and N2 adsorption-desorption (BET) analysis. Its removal process of chromium (III) and chromium (VI) on HKUST-1 was assessed systematically under various conditions such as pH value, shaking time and initial concentration of chromium (III). At pH 6.0–8.0, HKUST-1 were selective towards chromium (III) but hardly chromium (VI). Kinetic parameters fitted well with pseudo-second-order model and adsorption progress was described by Langmuir isotherm equations and spontaneous and endothermic according to the results of thermodynamics studies (?G?<?0, ?H?>?0, ?S?>?0). 相似文献
947.
Three novel rufigallol derivatives with four alkyl chains and two cholesteric units 6a, 6b and 6c were prepared in yields of 83–88%. The mesomorphic properties were investigated by DSC, POM and XRD analysis, suggesting that compounds 6a, 6b and 6c possess the ordered hexagonal columnar mesophase. The long alkyl chains contribute to the low phase transition temperature. Sample 6c with four dodecyl chains and two cholesterol units is a room temperature liquid crystal between 31°C and 87°C. Compounds 6a, 6b and 6c also have good fluorescence emission between 400 nm and 500 nm. The studies on CD spectra implied that the chiralities of cholesterol moieties are successfully transferred to the liquid crystalline core. Samples 6a, 6b and 6c are the first fluorescence liquid crystal based on rufigallol core with chiral cholesterol units. 相似文献
948.
Xiaoling Yang Jiayun Li Yu Liu Jiajian Peng Tianbo Li 《Phosphorus, sulfur, and silicon and the related elements》2019,194(1-2):83-86
The catalytic activities of titanium alkoxides and alkali metal alkoxides for hydrosilylation of unfunctionalized olefins have been studied. Titanium(IV) alkoxides showed excellent catalytic activity, while alkali metal alkoxides have low catalytic activity for the hydrosilylation of olefins. However, by using titanocene dichloride as an additive, alkali metal alkoxides showed also excellent catalytic property for hydrosilylation. In comparison with titanium alkoxides, no α-adduct was obtained by using alkali metal alkoxides/Cp2TiCl2 as catalysts. 相似文献
949.
With the ever‐increasing concerns on environmental pollution and energy crisis, it is of great urgency to develop high‐performance photocatalyst to eliminate organic pollutants from wastewater and produce hydrogen via water splitting. Herein, a polypyridyl‐based mixed covalent CuI/II complex with triangular {Cu3} and rhombic {Cu2Cl4} subunits alternately extended by mixed SCN– and Cl– heterobridges [Cu4(DNP)(SCN)Cl4]n ( 1 ) [DNP = 2,6‐bis(1,8‐naphthyridine‐2‐yl)pyridine] was solvothermally synthesized and employed as a dual‐functional co‐photocatalyst. Resulting from a narrowed band‐gap of 1.07 eV with suitable redox potential and unsaturated CuI/II sites, the complex together with H2O2 can effectively degrade Rhodamine B and methyl orange up to 87.4 and 88.2 %, respectively. Meanwhile, the complex mixed with H2PtCl6 can also accelerate the photocatalytic water splitting in the absence of a photosensitizer with the hydrogen production rate of 27.5 μmol · g–1 · h–1. These interesting findings may provide informative hints for the design of the multiple responsive photocatalysts. 相似文献
950.
Xiaodong Si Yuanyuan Jia Xinqi Luan Luo Yang Yong Pei Wang Zhou 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(9):2686-2690
A variety of benzofuranone‐based spiroisochromenes were originally designed and synthesized to gain insight into the oxa‐6π electrocyclic reaction of cis,cis‐1,8‐dioxatetraene for the first time. The stability of the 1,8‐dioxatetraene intermediate is governed by its steric congestion and can be fine‐tuned through modification of the backbone structure, leading to the reactivity differences in the 6π electrocyclic reaction and the emergence of photochromic properties. 相似文献