Hanmin Yang
South Central University for Nationalities
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Featured researches published by Hanmin Yang.
Langmuir | 2010
Bo Feng; Zhenshan Hou; Hanmin Yang; Xiangrui Wang; Yu Hu; Huan Li; Yunxiang Qiao; Xiuge Zhao; Qingfa Huang
The preparation, characterization, and catalytic properties of water-soluble palladium nanoparticles stabilized by the functionalized-poly(ethylene glycol) as a protective ligand were demonstrated for aerobic oxidation of alcohols in aqueous phase. UV/vis spectra and X-ray photoelectron spectroscopy (XPS) proved that there was an electronic interaction between the bidentate nitrogen ligand and palladium atoms. Transmission electron microscopy and XPS analysis showed that the particle size and surface properties of the generated palladium nanoparticles can be controlled by varying the amount of protective ligand and the kinds of reducing agents. It was found that both the size and surface properties of palladium nanoparticles played very important roles in affecting catalytic performance. The stabilized metallic palladium nanoparticles were proven to be the active centers for benzyl alcohol oxidation in the present system, and the water-soluble Pd nanocatalysts can also be extended to the selective oxidation of various alcohols.
Green Chemistry | 2014
Wenwen Zhu; Hanmin Yang; Jizhong Chen; Chen Chen; Li Guo; Huimei Gan; Xiuge Zhao; Zhenshan Hou
A sulfonic acid-functionalized silica-supported ruthenium catalyst (Ru/SiO2–SO3H) was employed for the hydrogenolysis of cellulose in one pot in neutral water medium. Ru/SiO2–SO3H is a bifunctional catalyst containing both a Bronsted acidic site and a metal site (Ru). Compared with the mechanical mixture of a silica-supported Bronsted acid (SiO2–SO3H) and a silica-supported Ru catalyst (Ru/SiO2), the bifunctional catalyst showed much higher yield of sorbitol, which could reach up to 61.2% when the reaction was performed for 10 h at 150 °C. Through the characterization by XPS and pyridine-adsorbed FT-IR, the existence of the interaction between sulfonic groups and Ru nanoparticles in the Ru/SiO2–SO3H catalyst was observed. The sulfonic acid groups and metal sites in the adjacent position were important for enhancing the yield of sorbitol. In addition, the present catalyst can be reused five times with only a slight decrease in yield of sorbitol in the consecutive recycles.
Chemistry: A European Journal | 2013
Wenwen Zhu; Yinyin Yu; Hanmin Yang; Li Hua; Yunxiang Qiao; Xiuge Zhao; Zhenshan Hou
The use of transition-metal nanoparticles/ionic liquid (IL) as a thermoregulated and recyclable catalytic system for hydrogenation has been investigated under mild conditions. The functionalized ionic liquid was composed of poly(ethylene glycol)-functionalized alkylimidazolium as the cation and tris(meta-sulfonatophenyl)phosphine ([P(C(6)H(4)-m-SO(3))(3)](3-)) as the anion. Ethyl acetate was chosen as the thermomorphic solvent to avoid the use of toxic organic solvents. Due to a cooperative effect regulated by both the cation and anion of the ionic liquid, the nanocatalysts displayed distinguished temperature-dependent phase behavior and excellent catalytic activity and selectivity, coupled with high stability. In the hydrogenation of α,β-unsaturated aldehydes, the ionic-liquid-stabilized palladium and rhodium nanoparticles exhibited higher selectivity for the hydrogenation of the C=C bonds than commercially available catalysts (Pd/C and Rh/C). We believe that the anion of the ionic liquid, [P(C(6)H(4)-m-SO(3))(3)](3-), plays a role in changing the surrounding electronic characteristics of the nanoparticles through its coordination capacity, whereas the poly(ethylene glycol)-functionalized alkylimidazolium cation is responsible for the thermomorphic properties of the nanocatalyst in ethyl acetate. The present catalytic systems can be employed for the hydrogenation of a wide range of substrates bearing different functional groups. The catalysts could be easily separated from the products by thermoregulated phase separation and efficiently recycled ten times without significant changes in their catalytic activity.
Journal of Colloid and Interface Science | 2014
Yinyin Yu; Wenwen Zhu; Li Hua; Hanmin Yang; Yunxiang Qiao; Ran Zhang; Li Guo; Xiuge Zhao; Zhenshan Hou
Ionic liquid (1-butyl-2,3-dimethylimidazolium acetate, [BMMIm]OAc)-Pluronic P123 mixed micelle stabilized water-soluble Ni nanoparticles were characterized by UV-vis, XRD, XPS and TEM and then employed for catalytic hydrogenation. It was demonstrated that the mixed-micelle stabilized Ni NPs showed excellent catalytic performance for the selective hydrogenation of CC and nitro compounds in the aqueous phase under very mild reaction conditions, and also the Ni NPs catalysts can be recycled at least for eight times without significant decrease in catalytic activity. The results of characterization revealed that the mixed micelle-stabilized Ni NPs catalysts were highly dispersed in aqueous phases even after five catalytic recycles. In addition, adding ionic liquid ([BMMIm]OAc) can affect the micelle structure of P123 solutions and thus afford an additional steric protection from aggregation of Ni NPs, resulting in enhancing stability and catalytic activity of Ni NPs.
Chinese Journal of Catalysis | 2011
Zhenyan Pan; Li Hua; Yunxiang Qiao; Hanmin Yang; Xiuge Zhao; Bo Feng; Wenwen Zhu; Zhenshan Hou
The supported silver catalyst Ag/KOH-γ-Fe2O3 was prepared by simple impregnation and liquid reduction and then structurally characterized by X-ray diffraction, transmission electron microscopy, and X-ray photoelectron spectroscopy. The supported silver catalysts were highly efficient for the epoxidation of styrene using tert-butyl hydroperoxide as the oxidant and ethyl acetate as the reaction medium. The addition of KOH was found to increase the catalytic activity and selectivity significantly. Additionally, the magnetically recoverable γ-Fe2O3, as a support, allowed for an easy separation and recycling of the catalyst after the reaction.
RSC Advances | 2016
Mengpan Wang; Hanmin Yang; Yinzheng Xie; Xiaohui Wu; Chen Chen; Wenbo Ma; Qifeng Dong; Zhenshan Hou
The one-pot hydrogenolysis of biomass-derived glycerol to 1-propanol has been investigated over sequential two-layer catalysts in a continuous-flow fixed-bed reactor. The zirconium phosphate layer was packed in the upper layer for dehydration of glycerol into acrolein and the supported Ru catalysts were in the second layer for the sequential hydrogenation of acrolein to 1-propanol. It was observed that the second layer catalyst with the strong acid sites would cause the formation of glycerol degradation products such as methanol, ethanol, methane and carbon dioxide etc., while 2%Ru/SiO2 with weak acid sites afforded the highest selectivity for 1-propanol. The sequential packing of zirconium phosphate and the 2%Ru/SiO2 catalytic system can give full glycerol conversions at 77% selectivity of 1-propanol, as well as exhibiting long-term stability (80 h). Carbonaceous deposits were a main reason for deactivation and the deactivated catalysts can be regenerated conveniently by calcinations in air. The present approach afforded an effective one-pot hydrogenolysis of glycerol to biopropanol, which could bring about the benign development of the biodiesel industry.
Catalysis Communications | 2012
Yu Shi; Hanmin Yang; Xiuge Zhao; Ting Cao; Jizhong Chen; Wenwen Zhu; Yinyin Yu; Zhenshan Hou
Advanced Synthesis & Catalysis | 2012
Bo Feng; Chen Chen; Hanmin Yang; Xiuge Zhao; Li Hua; Yinyin Yu; Ting Cao; Yu Shi; Zhenshan Hou
Catalysis Communications | 2009
Bo Feng; Li Hua; Zhenshan Hou; Hanmin Yang; Yu Hu; Huan Li; Xiuge Zhao
Catalysis Letters | 2009
Xiangrui Wang; Hanmin Yang; Bo Feng; Zhenshan Hou; Yu Hu; Yunxiang Qiao; Huan Li; Xiuge Zhao