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两类无机储氢材料的制备、表征及其储氢性能研究

Preparation, Characterization and Hydrogen Storage Poperties of Two Kinds of Inorganic Hydrogen Storage Materials

【作者】 马建丽

【导师】 陈军;

【作者基本信息】 南开大学 , 材料物理与化学, 2012, 博士

【摘要】 近年来,在高容量储氢材料的研究开发中,氨硼烷(AB)化合物的浸渍纳米填载技术已成为广大材料工作者的研究热点。与此同时,具有18电子结构的Mg基过渡金属氢化物也因其独特的结构备受人们的关注。本文综述了高容量储氢材料、介孔介质负载氨硼烷储氢材料以及具有18电子结构的Mg基过渡金属氢化物的研究进展。在此基础上,开展了介孔材料MCM-41及A-MCM-41负载AB的研究、介孔NiO制备及其负载AB的研究和镁基过渡金属氢化物储氢材料的制备及其表征研究。主要工作内容包括:(1)采用浸渍法,以四氢呋喃为溶剂,按照AB:MCM-41=1:2,1:1,2:1的比例制备负载材料AB/MCM-41,选用XRD、SAXRD、FTIR、氮气等温吸附、SEM、TEM等分析手段对负载材料进行表征。结果表明,AB:MCM-41=1:2的负载材料中的AB基本嵌入MCM-41中,呈现为了近程有序、远程无序的无定形相态;使AB:MCM-41=1:2负载材料在TG/DSC和TPD/MS的储氢性能测试中,免去了四方相向无定形态的转变,热解放氢温度降低了10°C,放氢过程中无氨气,但有硼嗪产生。(2)采用浸渍法,以含有4%Al2O3和96%SiO2的A-MCM-41为主体,四氢呋喃为溶剂,按照AB:A-MCM-41=1:2,1:1,2:1的比例负载客体AB。XRD、SAXRD、FTIR、氮气等温吸附、SEM、TEM等分析手段用于表征负载材料AB/A-MCM-41。结果表明,AB:MCM-41=1:2的负载材料中的AB完全嵌入A-MCM-41中,呈现为了近程有序、远程无序的无定形相态;使AB:A-MCM-41=1:2负载材料在TG/DSC和TPD/MS储氢测试中,免去了四方相向无定形态的转变,热解放氢温度降低近10°C,放氢过程中无氨气和硼嗪产生。(3)以水热法合成NiO(1):将蒸馏水:无水乙醇=1:1(体积比)的乙醇溶液75ml,六水氯化镍10mmol,尿素100mmol和十二烷基硫酸钠0.5g加入反应釜中,磁力搅拌混合后至110°C反应15h,再经抽滤、水洗、醇洗,80°C烘干12h,最后在电炉中以1°C/min的升温速率焙烧至300°C保温3h,制得黑色NiO(1)。产物与JCPDS No.65-6920相一致,为直径分布在50-70nm的实体近球形颗粒。将客体AB以AB:NiO(1)=1:1,1:2,1:4比例加载到NiO(1)中,以XRD、FTIR、SEM等表征负载材料AB/NiO(1),并以TG/DSC和TPD/MS对负载材料AB:NiO(1)=1:4的储氢性能进行测试。结果表明,AB:NiO(1)=1:4负载材料的热解放氢温度与原料AB相差仅3.6°C,但放氢过程中无氨气和硼嗪产生。(4)以均匀沉淀模板法合成NiO(2):按照六水氯化镍:十二烷基硫酸钠:尿素:蒸馏水为20:40:600:1200的摩尔比混合,在40°C水域中搅拌0.5-1h,随后置入80°C烘箱均匀沉淀20h,再经抽滤、水洗、醇洗,60°C烘干12h,最后在电炉中以1°C/min的升温速率焙烧至300°C并保温3h,制得NiO(2)粉末与JCPDS No.65-2091相一致,为由薄片卷曲而成的球型颗粒。将客体AB以AB:NiO(2)=1:1,1:2,1:4比例加载到NiO(2)中,以XRD、FTIR、SEM等表征负载材料AB/NiO(2),并以TG/DSC和TPD/MS对负载材料AB:NiO(2)=1:4的储氢性能进行测试。结果表明,AB:NiO(2)=1:4负载材料的热解放氢温度与原料AB相差10.2°C,放氢过程中无氨气和硼嗪产生。(5)以回流非模板法合成NiO(3):按照六水氯化镍:六次甲基四胺:蒸馏水为20:200:350000的摩尔比混合,在140°C加热回流2.5h,再经抽滤、水洗、醇洗,60-70°C烘干12h,最后在电炉中以1°C/min的升温速率焙烧至300°C并保温3h,得到NiO(3)粉末与JCPDS No.89-7130相一致,为由薄片交织而成的网状体。以AB:NiO(3)=1:1,1:2,1:4比例负载AB,以XRD、FTIR、SEM等表征负载材料AB/NiO(3),并以TG/DSC和TPD/MS对负载材料AB:NiO(3)=1:4的储氢性能进行测试。结果表明,AB:NiO(3)=1:4负载材料的热解放氢温度与原料AB相差2.2°C,放氢过程中无氨气和硼嗪产生。(6)采用反应球磨法制备镁基过渡金属氢化物。以纳米Fe:微米MgH2=1:3摩尔比混合并球磨55h,制得与JCPDS No.38-843相一致的Mg2FeH6相,产物中含有未反应的Fe和MgH2。相类似,以纳米Co:微米MgH2=2:5摩尔比混合并球磨12h,完全反应制得与JCPDS No.78-215相一致的纳米晶Mg2COH5相,经HRTEM的FFT转换分析,Mg2CoH5的(101)晶面间距为0.366nm。

【Abstract】 Recently, hydrogen storage materials of ammonia borane compound with highgravimetric hydrogen capacity have become the research focus by nano-loadingtechnology. In the meantime, Mg-based transition metal hydrides with18electronicstructure have also attracted much attention because of their uniquestructure. Thisarticle reviews the research progress of high-capacity hydrogen storage materials, themesoporous medium loading of ammonia borane hydrogen storage materials, as wellas Mg-based transition metal hydrides with18electronic structure. On this basis, thepaper expands the research of the loading of AB in mesoporous material MCM-41and A-MCM-41, the preparation of mesoporous NiO and its loading of AB, and thepreparation and characterization of magnesium-based transition metal hydrides. Themain contents include:(1)AB/MCM-41samples were synthesized by an impregnation method intetrahydrofuran (THF) at room temperature. The ratios of AB: MCM-41are fixed at1:2,1:1, and2:1. The as-prepared samples have been characterized by XRD,SAXRD, FTIR, BET, SEM, and TEM. The results show that most AB was loadedinto the MCM-41with short-range ordered and long-range disorderd phase. TheTG/DSC and TPD/MS investigations show that the AB: MCM-41=1:2sampledecreased the dehydrogenation temperature of AB for10°C without NH3releasingbut with borazine.(2)AB: A-MCM-41samples were synthesized by an impregnation method intetrahydrofuran (THF) at room temperature. The ratios of AB: A-MCM-41are fixedat1:2,1:1, and2:1. The as-prepared samples have been characterized by XRD,SAXRD, FTIR, BET, SEM, and TEM. The results show that AB was loaded into theA-MCM-41with short-range ordered and long-range disorderd phase. The TG/DSCand TPD/MS investigations show that the AB: A-MCM-41=1:2sample decreasedthe dehydrogenation temperature of AB for10°C without any borazine or NH3releasing. (3)NiO(1) was synthesized by a hydrothermal method at the conditions andprocesses of distilled water: ethanol=1:1(volume ratio) with ethanol solution75ml,six nickel chloride10mmol, urea100mmol, and sodium dodecyl sulfate0.5g addedto the reactionkettle, stirred the mixture and heated to110°C for15h, then filtered,washed with water and alcohol, drying at80°C for12h, and finally calcined in thefurnace to300°C with a heating rate of1°C/min for3h. The as-prepared blackNiO(1) is nearly spherical particles with the diameter of50-70nm. AB was loadedinto NiO(1) with the AB:NiO(1) ratio of1:1,1:2, and1:4. The as-prepared sampleshave been characterized by XRD, FTIR, SEM, TG/DSC and TPD/MS. The resultsshow that the sample with the ratio of AB:NiO(1)=1:4suppressed the releasing ofborazine and NH3, and decreased the dehydrogenation temperature for3.6°C.(4)NiO(2) was synthesized by a homogeneous precipitation-template methodin the following conditions: the molar ratio of nickel chloride: sodium dodecylsulfate: urea: distilled water is20:40:600:1200, the mixture stirred in water bath for40°C for0.5-1h, placed in an oven for drying at80°C for20h, filtered, washed withwater and alcohol, dried at80°C for12h, and finally calcined in the furnace to300°C with a heating rate of1°C/min for3h. The obtained NiO(2) powder is consistentwith the JCPDS No.65-2091. NiO(2) is flasks which are consisting of sphericalparticles. AB was loaded into NiO(2) with the AB:NiO(2) ratios of1:1,1:2, and1:4.The as-prepared samples have been characterized by XRD, FTIR, SEM, TG/DSCand TPD/MS. The results show that the AB:NiO(2)=1:4sample suppressed thereleasing of borazine and NH3, and decreased the dehydrogenation temperature for10.2°C.(5)NiO(3) was synthesized by a reflux method in the conditions of the molarratio of nickel chloride: hexamethylenetetramine: distilled water is20:200:350000.The mixture was refluxed at140°C for2.5h, filtered, washed with water and alcohol,dried at80°C for20h, and finally calcined in the furnace to300°C with a heatingrate of1°C/min for3h. The obtained NiO(3) powder powder is consistent with theJCPDS No.89-7130. NiO(3) is consisting of flasks. AB was loaded into NiO(3) withthe AB:NiO(3) ratio of1:1,1:2, and1:4. The as-prepared samples have beencharacterized by XRD, FTIR, SEM, TG/DSC and TPD/MS. The results indicate that the sample with the ratio of AB:NiO(3)=1:4suppressed the releasing of borazine andNH3, and decreased the dehydrogenation temperature for3.2°C.(6)Mg-based transition metal hydrides were synthesized by ball-millingmethod. The molar ratio of nano-Fe: micro-MgH2is1:3. The mixture was milled for55h. The obtained Mg2FeH6phase is consistent with the JCPDS No.38-843. Theproduct contains unreacted Fe and MgH2. Similarly, the molar ratio of nano-Co:micro-MgH2is2:5. The obtained Mg2CoH5phase is consistent with the JCPDS No.78-215. The conversion analysis by HRTEM and FFT shows that the crystal planespacing of Mg2CoH5(101) is0.366nm.

  • 【网络出版投稿人】 南开大学
  • 【网络出版年期】2014年 06期
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