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Preparation and characterization of sulfated TiO_2 with rhodium modification used in esterification reaction and decomposition of methyl orange 被引量:3
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作者 Yu Niu fuying li +3 位作者 Kai Yang Ting Qiu Renzhang Wang Cheng lin 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2016年第6期767-774,共8页
A unique Rh/TiO_2 solid acid catalyst modified with H_2SO_4 was synthesized and evaluated in the esterification reaction of propylene glycol methyl ether and decomposition of methyl orange(MO) in aqueous phase under h... A unique Rh/TiO_2 solid acid catalyst modified with H_2SO_4 was synthesized and evaluated in the esterification reaction of propylene glycol methyl ether and decomposition of methyl orange(MO) in aqueous phase under halogen lamp irradiation. For this purpose, rhodium(Rh) nanoparticles were loaded on SO_4^(2-)/TiO_2 via the photo-deposition method. It was found that SO_4^(2-)/Rh–TiO_2 exhibited stronger catalytic activity than SO_4^(2-)/TiO_2. The new catalysts were characterized by X-ray powder diffraction(XRD), Brunauer–Emmett–Teller(BET), Transmission electron microscopy(TEM) and high-resolution(HRTEM), X-ray photoelectron spectroscopy(XPS) and Fourier Transform infrared spectroscopy(FTIR). Results from XRD and BET show that SO_4^(2-)/Rh–TiO_2 has higher specific surface area and smaller pore size than SO42-/TiO_2. The distribution of loaded Rh was found to be uniform with a particle size of 2–4 nm. Data from XPS reveal that Rh primarily exists as Rh^0 and Rh^(3+)in Rh–TiO_2 and SO_4^(2)-/Rh–TiO_2. These valence forms of Rh likely contribute to the enhanced catalytic activity. Furthermore, FT-IR spectra of the catalysts show an abundance of surface hydroxyl groups, which help the formation of hydroxyl radicals and the enhancement of surface acid density. The results show that more acid sites are formed on the sulfated Rh–TiO_2, and these acidic sites are largely responsible for improving the catalytic performance. This superior SO_4^(2-)/Rh–TiO_2 catalyst has potential applications in reactions requiring efficient acid catalysts, including esterification reactions and waste water treatment. 展开更多
关键词 酯化反应 TiO2 甲基橙 硫酸 傅里叶变换红外光谱 催化剂改性 X-射线粉末衍射 X射线光电子能谱
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Drag Characteristics Prediction for Wet Multi-Disk Brakes 被引量:1
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作者 Tianhong Luo Zhongtao li fuying li 《Journal of Beijing Institute of Technology》 EI CAS 2019年第3期549-560,共12页
To improve the characteristics of wet multi-disc brakes (WMDBs), the WMDBs of the drive axles of mining trucks were studied. A model was established to predict the phenomenon of drag characteristics during wet brake n... To improve the characteristics of wet multi-disc brakes (WMDBs), the WMDBs of the drive axles of mining trucks were studied. A model was established to predict the phenomenon of drag characteristics during wet brake non-engagement by considering the combined effect of surface grooves, film shrinkage, and laminar Navier-Stokes (N-S) equations. The model was used to study drag torque and temperature variation of the wet brakes for different volume flows, dynamic viscosities, and friction pair clearances. The simulation results indicated that the peak torque decreased when the clearance of the friction pair increased. Additionally, the peak torque increased when the volume flow increased and when the cooling liquid dynamic viscosity increased. The model was more accurate than a traditional forecasting system when considering the role of surface grooves and oil film shrinkage in actual working conditions. 展开更多
关键词 WET BRAKE drag TORQUE combined effects MULTI-PARAMETER PREDICTION system
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