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61.
Jiafu Qu Yueqiang Cao Xuezhi Duan Najun Li Qingfeng Xu Hua Li Jinghui He Dongyun Chen Jianmei Lu 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(35):12386-12391
Toxic gases that are colorless and odorless, such as CO, are a major environmental concern and require early detection to prevent serious toxicological effects. In this study, a unique system (Pt/HMSs‐BRC) was fabricated by combining a catalyst (Pt/hollow mesoporous silica spheres, Pt/HMSs) with a silica gel containing an adsorbed chromogenic probe (binuclear rhodium complex, BRC). The process is a simple method to prepare well‐dispersed and uniform Pt nanoparticles. The Pt/HMSs‐BRC materials demonstrated early CO detection and excellent catalytic performance for CO oxidation. The probe exhibited remarkable color modulation from gray‐violet to light‐yellow when exposed to CO concentration levels above 50 ppm, and the color of the chromogenic probe was fully recoverable. By a kinetics‐assisted discrimination method and DFT calculations, it was found that the corner Pt sites are the dominant active sites for CO oxidation. 相似文献
62.
LI Hongda ZHAO Zhen LI Jiacheng LI Jianmei ZHAO Linlin SUN Jiachen FAN Xiaoqiang 《高等学校化学研究》2019,35(5):866-873
A novel composite material of TS-1@SBA-16 was synthesized by enwrapping TS-1 zeolite crystals with mesoporous SBA-16 silica. This composite was used as catalyst support for loading Pt-SnOx in the propane dehydr genation(PDH) reaction. Catalysts were characterized by means ofN2 adsorption-desorption, XRD, SEM, TEM, XPS, UV-Vis, and Raman spectroscopy. The effect of different contents of TS-1 on PDH was investigated, and the optimal amount of TS-1 was determined to be 10%. The catalyst with TS-1 content of 10% showed the highest PDH activity and the initial conversion of propane over it can achieve 54.5%, higher than those over TS-1 or SB A-16-supported ones. The superior catalytic performance of Pt-SnOx/TS-1 @SBA-16 is related to the synergistic effect of the excellent mass transfer performance through the hierarchical porous structure, suitable acid acidity and electronic effect of Ti species. 相似文献
63.
A hybrid system of carbon nanotubes (CNTs) coated with poly (amidoamine) (PAMAM) dendrimer-encapsulated platinum nanoparticles (Pt-DENs) and glucose oxidase (GOx) was prepared through the layer-by-layer (LbL) self-assembly approach and then used as anode in enzyme-based biofuel cells (BFCs). The assembly process was monitored by ζ-potential measurement, and the as-resulted Pt-DENs/CNTs nanocomposites were characterized by transmission electron microscopy (TEM). The performance of electrodes modified by Pt-DENs/CNTs was also investigated by electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV). We found that the Pt-DENs/CNTs could enhance the electron transfer between the redox centers in enzyme and the electrode surfaces. Furthermore, by employing the Pt-DENs/CNTs modified electrodes as anode, the enzyme-based BFCs operated in a solution containing glucose generated an open-circuit voltage of approximately 640.0 mV and a maximum current density of about 90.0 μA/cm2, suggesting that Pt-DENs/CNTs may serve as an alternative anode to previously used noble metals in BFC applications. 相似文献
64.
The conversion of biomass faces the challenge of mass and heat transfer, as well as the exertion of heterogeneous catalyst, because raw biomass exists usually in solid state. In this work, the simultaneous transformation and dissolution of the three main components (hemicellulose, cellulose, lignin) in corn straw were achieved in ethanol/ valerolactone (GVL)/H2O (10 : 10 : 40, v/v/v) co‐solvent system. With the assistance of AlCl3 ⋅ 6H2O, the conversion of hemicellulose, lignin and cellulose was >96 % at 170 °C. The conversion of solid biomass into fluid, overcoming the mass transfer restrictions between solid biomass and solid catalysts, provides new raw materials to further upgrading. H2O could penetrate inside the crystalline cellulose to swell even dissolve it, while ethanol and GVL acted as media to dissolve especially the G unit in lignin. The H+ derived from AlCl3 ⋅ 6H2O hydrolysis could break the linkages of lignin‐hemicellulose and glycosidic bond in saccharides, and aluminum chloride promoted the next degradation of polysaccharides to small molecules. Consequently, as high as 33.2 % yield of levulinic acid and 42.2 % yield of furfural were obtained. The cleavage of β‐O‐4 and Cβ−Cγ bonds in lignin produced large amounts of lignin‐derived dimers and trimers. The total yield of monomeric phenols is up to 8 %. 相似文献
65.
Xiaoqiang Fan Jianmei Li Zhen Zhao Yuechang Wei Jian Liu Aijun Duan Guiyuan Jiang 《天然气化学杂志》2014,(2):171-178
Highly ordered mesoporous NiMoO4material was successfully synthesized using mesoporous silica KIT-6 as hard template via vacuum nanocasting method. The structure was characterized by means of XRD, TEM, N2adsorption-desorption, Raman and FT-IR. The mesoporous NiMoO4with the coexistence of α-NiMoO4and β-NiMoO4showed well-ordered mesoporous structure, a bimodal pore size distribution and crystalline framework. The catalytic performance of NiMoO4was investigated for oxidative dehydrogenation of propane. It is demonstrated that the mesoporous NiMoO4catalyst with more surface active oxygen species showed better catalytic performance in oxidative dehydrogenation of propane in comparison with bulk NiMoO4. 相似文献
66.
钙钛矿型稀土镓酸盐的光谱性质 总被引:2,自引:0,他引:2
本文得到LaGaO3晶体室温下的激发光谱和荧光光谱,发现LaGaO3晶体能够产生可见荧光,并且荧光谱线比粉末状LaGaO3变窄.测定了室温下LnGaO3(Ln=La,Pr,Na)晶体的吸收光谱,对红外吸收光谱给出了理论点阵振动数目和对称类型,研究了晶体经退火处理对吸收光谱的影响.对粉末状 LaGaO3:Ln(Ln=Ce,Sm,Tb)研究了合成温度及掺杂稀土离子浓度对光谱结构的影响. 相似文献
67.
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69.
Zhenping Cheng Xiulin Zhu Gaojian Chen Wenjian Xu Jianmei Lu 《Journal of polymer science. Part A, Polymer chemistry》2002,40(21):3823-3834
The reverse atom transfer radical polymerization (RATRP) of methyl methacrylate (MMA) was successfully carried out under pulsed microwave irradiation (PMI) at 69 °C with N,N‐dimethylformamide as a solvent and with azobisisobutyronitrile (AIBN)/CuBr2/tetramethylethylenediamine as an initiation system. PMI resulted in a significant increase in the polymerization rate of RATRP. A 10.5% conversion for a polymer with a number‐average molecular weight of 34,500 and a polydispersity index of 1.23 was obtained under PMI with a mean power of 4.5 W in only 52 min, but 103 min was needed under a conventional heating process (CH) to reach a 8.3% conversion under identical conditions. At different [MMA]0/[AIBN]0 molar ratios, the apparent rate constant of polymerization under PMI was 1.5–2.3 times larger than that under CH. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 3823–3834, 2002 相似文献
70.
扩展了YGa3B4O12的合成温度。研究了合成的改变及Cr^3+离子引入后发光性质的变化。合成YGa3-xCrxB4O12化合物后,对其磁学性质进行了表征。结果表明,高温合成该化合物有利于人合物芝光发射的增强,掺杂少量Cr^3+可以稳定该化合物春发光光谱。磁化率随Cr^3+含量的增加而增大。 相似文献