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| 1 | Synthesis of hexaaluminate catalysts for methane combustion by reverse microemulsion medium显示文摘The aim of this study is to synthesize the catalysts of Fe-and Mn-substituted hexaaluminate by reverse microemulsion medium for methane catalytic combustion application.Pseudo-ternary phase diagrams in quaternary microemulsion systems of cetyltrimethylammonium bromide(CTAB),n-butanol,n-octane,and water [or Al(NO3)3 solution] were presented.The effects of the alcohol chain length,ratio of sur-factant to cosurfactant,and salt concentration on the formation and stability of microemulsion systems were studied.The phase behavior of microemulsion systems was confirmed through the varying of the conductivity with the water content.The performance and structure of the catalysts,La(Mnx/Fex)Al12-x-O19-δ synthesized with the optimal parameter in the phase diagrams of microemulsions systems were characterized by BET,TG-DTA,and XRD.The micro fix-bed reactor was used to measure the catalytic activities of catalysts to methane combustion.The results showed that this synthesis method could yield non-agglomerated and highly dispersed precursors that would undergo crystallization at the lower temperature of 950℃.When temperature was raised up to 1050℃,the complete crystalline La-hexaaluminate was shaped.The hexaaluminate substituted with Fe had high-catalytic activity and stability at high temperature,while the Mn-substituted had higher catalytic activity at lower temperature.When the cooperation of Fe and Mn occurred,i.e.,LaFeMnAl10O19-δ exhibited a high surface area and catalytic activity to CH4 combustion,the CH4 light-off temperature was only 475℃ and the complete combustion temperature was 660℃.This was attributed to the synergistic effect between Fe and Mn. | BAI ShouLi WANG LiangShi SHI BingJie YANG PengCheng CUI MeiSheng LONG ZhiQi LI DianQing CHEN AiFan | 2009 | Science China Chemistry2009，52，1： | 6 |
| 2 | Synthesis of ZnO nanorods and its application in NO 2 sensors显示文摘 | Shouli Bai Xin Liu Dianqing Li Song Chen Ruixian Luo Aifan Chen | 2010 | Sensors & Actuators: B Chemical2010，，1： | 1 |
| 3 | Sn/In/Ti nanocomposite sensor for CH 4 detection显示文摘 | Bai Shouli Chen Liangyuan Yang Pengcheng Luo Ruixian Chen Aifan Chung Chiun Liu | 2008 | Sensors & Actuators: B Chemical2008，，1： | 1 |
| 4 | Effect of planar structures on the anisotropy of Ranyah sandstone, Saudi Arabia显示文摘 | Abbas Aifan Al-Harthi | 1998 | Engineering Geology1998，，： | 1 |
| 5 | Preparation, characterization of WO 3 –SnO 2 nanocomposites and their sensing properties for NO 2显示文摘 | Shouli Bai Dianqing Li Dongmei Han Ruixian Luo Aifan Chen Chiun Liu Chung | 2010 | Sensors & Actuators: B. Chemical2010，，： | 1 |
| 6 | Synthesis of La-hexaaluminate catalyst for methane combustion by a reverse SDS microemulsion显示文摘La-hexaaluminate catalyst for methane catalytic combustion was synthesized by a reverse microemulsion.Pseudo-ternary phase diagrams of a quaternary microemulsion system of sodium dodecyl sulfate(SDS),n-pentanol,n-octane,and water(or Al(NO3)3 solution) were presented.The effects of alcohol chain length,cosurfactant-to-surfactant ratio,and salt concentration on the formation and stability of the microemulsion system were studied.The phenomenon that the conductivity changed with water supported the phase behavior of the microemulsion system.La(Mnx/Fex)Al12-xO19-δ catalysts,applied in methane combustion and with high-temperature stability,were synthesized within the stable areas of the phase diagram of the microemulsion system,when SDS was chosen as surfactant,n-pentanol as cosurfactant,and n-octane as oil phase.The physical properties and structure of the catalysts were characterized by BET method,transmission electron microscope(TEM),and X-ray diffraction(XRD).A micro-fixed-bed reactor was used to measure the catalytic activity of hexaaluminates in methane combustion.The results show that the reverse microemulsions can be used to produce discrete La-hexaaluminate nanoparticles that display excellent methane combustion activity owing to their high surface area and high thermal stability. | YU Ying WANG Liangshi CUI Meisheng SHI Yongxi LUO Ruixian CHEN Aifan | 2011 | Rare Metals2011，30，4： | 0 |
| 7 | Catalytic combustion properties of nanocomplex oxide for natural gas显示文摘The catalysts of copper oxide supported on cerium dioxide were prepared by different methods for methane catalytic combustion. The effects of copper content in the catalysts and calcination temperatures of the catalysts on the catalytic activity are investigated. Results show that the complex oxide catalyst exhibits high catalytic activity for methane combustion due to the synergistic effect of CuO and CeO2. The catalyst prepared by impregnation is more active than that prepared by controlled coprecipitation even if CuO content is the same. When W(CuO) <13%, the light-off temperature and full conversion temperature for the CH4 reaction decrease with the increasing of CuO content in the catalysts. However, when the copper content is above 13%, the excess CuO has a negative effect on the catalytic activity owing to the formation of bulk CuO particles. A proper calcinations temperature of 650 ℃ can lead to a high dispersion of CuO and accordingly can enhance the catalytic activity of the composites. | MA Lijing YANG Dong LI Yingxia CHEN Aifan LUO Ruixian | 2005 | Progress in Natural Science:Materials International2005，15，11： | 0 |
| 8 | Synthesis of LaFeO_3 catalytic materials and their sensing properties显示文摘LaFeO3 is a p-type semiconductor catalytic material of perovskite structure (ABO3). Its magnetic and photocatalytic properties have been widely investigated,but the gas sensing properties are seldom reported,especially for toxic and noxious gases of NO2 and CO. The nanocomposites of LaFeO3 and LaFe1-xMgxO3 (x = 0.02,0.04,0.06) were prepared by various methods of the wet chemical process and their exact composition,crystal structures,grain sizes,specific surfaces,morphology and the electronic interaction between components were characterized by EDX,XRD,BET,SEM and XPS analysis. The sensors based on these nanocomposites have been fabricated to examine the sensing responses to gases,and the results show that these sensors exhibited high response to both oxidizing gas (NO2) and reducing gas (CO),and the response was greatly enhanced by the surface modification of MgO. The additive method,amount of additives,and their effects on the LaFeO3 structure and gas response have been analyzed and discussed by temperature-programmed desorption (TPD) and X-ray photoelectron spectroscopic (XPS) analysis. | BAI ShouLi,SHI BingJie,MA LiJing,YANG PengCheng,LIU ZhiYong,LI DianQing & CHEN AiFan State Key Laboratory of Chemical Resource Engineering,College of Science,Beijing University of Chemical Technology,Beijing 100029,China | 2009 | Science China Chemistry2009，52，12： | 0 |
| 9 | Catalytic activity of Mn-substituted barium hexaaluminates for methane combustion显示文摘The catalysts of hexaaluminate (BaMnxAl12-xO19-δ , x = 1.0, 2.0, 3.0, 4.0) to be used in methane combustion have been successfully synthesized by co-precipitation method and supercritical drying. The crystalline structure and surface area of catalyst were characterized by X-ray diffraction (XRD) and nitrogen adsorption analysis of BET method. BET analysis revealed that the preparing and drying method proposed here provides stable materials with higher surface area of 51.4 m2/g in comparison to materials prepared using conventional ambient drying method for BaMnxAl12?xO19-δ calcined at 1200℃ under oxygen. XRD analysis indicated that formation of a pure single phase BaMnxAl12-xO19-δ occurred up to x = 3 in the case of Mn-substituted barium hexaaluminates. Incorporation of Mn in excess leads to BaAl2O4 phase formation. As far as the valence state of Manganese ions was concerned, the introduced Mn ions were either divalent or trivalent. The first Mn ions were introduced in the matrix essentially as Mn2+ and only for BaMn3Al9O19-δ does manganese exist exclusively as Mn3+; the higher the Mn concen- tration, the higher the proportion of Mn3+. Catalytic activity for methane combustion has been measured for Mn-substituted barium hexaaluminates, light-off temperature was observed in the 512-624℃ range. The highest activity was obtained for catalysts containing 3 Mn ions per unit cell, which reveals that the BaMnxAl12-xO19-δ catalyst was a promising methane combustion catalyst with high activity and good thermal stability. Temperature programmed reduction (TPR) under hydrogen has been used to correlate the catalytic activity with the amount of easily reducible species. | MA LiJing SHI BingJie CUI MeiSheng WANG LinHong LI DianQing CHEN AiFan | 2008 | Science China Chemistry2008，51，3： | 0 |
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