纳米金属粉及Fe2O3对高氯酸铵热分解的催化性能研究

用热分析法研究了纳米金属粉(Ni,Cu和Al)以及纳米Fe2O3对高氯酸铵(AP)热分解的催化性能.结果表明,质量分数为5%的纳米镍粉、铜粉和铝粉可以明显降低AP的高温分解温度,显示出对AP高温分解反应很好的催化活性;纳米铜粉对AP的低温分解也有很好的催化作用,而纳米镍粉和铝粉却表现出对AP低温分解反应具有一定的阻碍作用.微米级金属粉对AP高温分解反应的催化作用明显小于纳米金属粉.纳米Fe2O3对高氯酸铵的高温分解具有很好的催化效果,并且其催化效果明显优于微米Fe2O3.纳米Fe2O3与AP进行复合处理,可以提高纳米Fe2O3粒子对AP的催化性能.     

纳米Ni及碳纳米管对AP热分解的催化性能

分别用溶液还原法和化学沉淀法制备出了纳米NiNi／CNTs复合催化剂粒子,并用TEM,SEM,XRD,FT—IR对其进行了表征;运用差热分析（DTA）研究了纳米Ni及Ni／CNTs复合催化剂粒子对AP热分解性能的影响。结果表明。纳米Ni使AP热分解的高温分解峰温降低104．47C,纳米Ni／CNTs复合催化剂粒子可使AP热分解的高温分解峰温降低137．05℃,证明碳纳米管在纳米Ni对AP热分解的催化过程中起到了很好的助催化作用。     

碳纳米管/高氯酸铵复合粒子的制备及热分解性能

采用溶剂蒸发法制备了碳纳米管（CNTs）／AP复合粒子，并用TEM，SEM，FT—IR和XRD对其进行表征，用DTA研究了纳米复合粒子中CNTs对AP热分解的催化性能，并与纯AP以及相同含量的CNTs与AP简单混合物进行对比。结果表明，CNTs对AP的热分解有一定的催化作用，且CNTs／AP复合粒子中CNTs对AP的催化性能优于CNTs与AP的简单混合物；与纯AP样品相比，复合粒子中AP的高温分解峰温降低了113．9℃，低温分解峰几乎消失，表观分解热由309．92J／g提高到984．18J／g，而CNTs与AP简单混合样的表观分解热为709．50J／g，表明CNTs与AP的复合处理可改善AP的高温热分解性能。     

纳米Cu-Cr复合金属氧化物的机械研磨制备及对AP的催化性能

为了增强纳米氧化铜对高氯酸铵(AP)热分解的催化作用,采用机械研磨法批量制备了一系列摩尔比分别为1∶2, 1∶1, 1∶0.5, 1∶0.25的CuO/Cr_2O_3纳米Cu-Cr复合金属氧化物(纳米CuO/Cr_2O_3);采用X射线衍射(XRD)、扫描电子显微镜(SEM)和透射电子显微镜(TEM)表征样品的微结构、表面元素和形态;通过热重(TG)分析和差示扫描量热(DSC)技术研究了纳米Cu-Cr复合金属氧化物对AP热分解的催化作用,讨论了纳米CuO/Cr_2O_3含量对AP热分解的影响。结果表明,与其他纳米Cu-Cr复合金属氧化物、单一纳米CuO和纳米Cr_2O_3相比,质量分数2%的CuO/Cr_2O_3(摩尔比1∶0.25)复合金属氧化物对AP热分解具有最佳催化效果,可使AP的分解温度从441.3℃下降到351.1℃,吉布斯自由能从199.8kJ/mol降至172.1kJ/mol,同时表观分解热从941J/g升至1778J/g,这可能是由于在高能研磨力场下,纳米CuO和纳米Cr_2O_3发生晶格变化促进其对AP热分解的协同催化作用。     

纳米钛酸锌的制备及其对AP热分解性能的影响

以四氯化钛、六水硝酸锌为原料,碳酸铵为沉淀剂,制备了纳米ZnTiO3的粉体,用X射线衍射、红外光谱和透射电镜等对产物进行表征,用差热分析考察了纳米ZnTiO3对高AP热分解的催化作用.结果表明,在550℃可制得结晶良好的立方相纳米ZnTiO3,呈球形或近似球形,粒径约100 nm.在AP中加入质量分数5%的纳米ZnTiO3,AP的低温和高温热分解峰分别提前约18.3℃和25.1℃;提高纳米ZnTiO3的含量可以增强对AP高温热分解反应的催化作用,阻碍AP的低温热分解.     

CuO/Al复合材料的制备及对高氯酸铵的催化作用

为了改善固体推进剂中高氯酸铵(AP)的热分解性能,利用溶胶-凝胶法制备了CuO/Al复合催化剂,并利用SEM、XRD、EDS对其形貌和结构进行了表征,通过DSC考察了催化剂对AP热分解的催化效果。结果表明:CuO/Al复合催化剂结构完整,其对AP的催化效果明显优于普通CuO+Al混合物的催化效果,并对比了加入1%、3%、5%质量分数的CuO/Al复合催化剂对AP的催化效果,发现当加入CuO/Al质量分数为5%时,低温分解峰和高温分解峰分别降为289.4和318.0℃,表明所制备的CuO/Al复合催化剂可有效降低AP的热分解温度,改善其热分解性能。     

覆碳铁、钴、镍纳米复合材料对AP的催化热分解

通过400℃，500℃、600℃热解含Fe，Co，Ni的高聚物前驱体（M-PAA，M为Co，Fe，Ni）制备覆碳的Fe，Co，Ni纳米复合材料（M／C），研究了其对AP热分解的影响。XRD和TEM结果表明，500℃热解M-PAA均可获得纳米Fe（Co或Ni）／C材料，热解产物中Co，Fe，Ni颗粒的平均粒径分别为13nm，18nm和20nm。DTA研究结果表明，添加500℃热解所得的M／C（M／C-500）对AP的热分解有明显的催化作用，其催化作用随着M／C-500添加量的增加而增加，Ni／C-500，Fe／C-500，Co／C-500分别使AP高温分解峰最大可降低54．5℃，79．3℃和156．2℃。其中Co／C-500可使AP的高温和低温分解峰发生重叠。     

高氯酸铵/石墨烯纳米复合材料的制备及热分解行为

通过溶胶-凝胶法制备了高氯酸铵/石墨烯气凝胶(AP/GA)纳米复合材料,用SEM、元素分析和XRD对其结构进行了表征,用TG-DSC-IR联用技术对其热分解行为进行了研究.结果表明,AP/GA纳米复合材料中,AP以纳米尺寸存在于石墨烯气凝胶中,AP质量分数高达94.4％,平均粒径约为69.41 nm.石墨烯对AP的热分解过程具有明显的催化作用,与AP相比,AP/GA纳米复合材料的低温分解峰消失,高温分解峰温降低了83.7℃.总分解热达2110J/g.     

纳米SiO2负载的过渡金属硼化物对AP热分解的催化作用

采用化学还原法制备纳米NiB/SiO2、CoB/SiO2、MoB/SiO2催化剂,通过热重-差热分析(TG-DTA)研究了其对AP热分解过程的催化作用.结果表明,负载过渡金属硼化物催化剂对AP分解的催化活性顺序为:CoB/SiO2＞NiB/SiO2＞ MoB/SiO2;加入质量分数5％的CoB/SiO2使AP高温热分解峰温度降低166.2℃;SiO2载体将CoB晶型转化推迟了 110℃左右,改善了催化剂的热稳定性.     

纳米CuCr_2O_4的制备及其对AP热分解性能的影响

采用HLG-5型纳米化粉碎机制备了粒径约为60nm的纳米CuCr2O4,用X射线衍射仪(XRD)、透射电子显微镜(TEM)表征了样品的结构及形貌,分析了纳米CuCr2O4的形成机理,用差示扫描量热仪(DSC)研究了原料CuCr2O4和纳米CuCr2O4对AP热分解性能的影响。结果表明,与原料CuCr2O4相比,质量分数2%的纳米CuCr2O4对AP具有更好的催化性能,可使AP的低温分解峰减弱,高温分解峰温降低67℃,反应速率常数提高数倍,使AP的表观分解热从821J/g提高到1 393J/g,增长率为69.7%。     

纳米级金属和金属复合物粉末对高氯酸铵和高氯酸铵/聚合丁二烯复合固体推进剂热分解特性的影响

Effects of metal (Ni, Cu, Al) and composite metal (NiB, NiCu, NiCuB) nanopowders on the thermal decomposition of ammonium perchlorate (AP) and composite solid propellant ammonium perchlorate/hydroxyterminated polybutadiene (AP/HTPB) were studied by thermal analysis (DTA). The results show that metal and composite metal nanopowders all have good catalytic effects on the thermal decomposition of AP and AP/HTPB composite solid propellant. The effects of metal nanopowders on the thermal decomposition of AP are less than those of the composite metal nanopowders. The effects of metal and composite metal nanopowders on the thermal decomposition of AP are different from those on the thermal decomposition of the AP/HTPB composite solid propellant.     

Effects of Nanometer Ni,Cu, Al and NiCu Powders on the Thermal Decomposition of Ammonium Perchlorate

A study of the decomposition behaviour for Ammonium Perchlorate(AP) was carried out by differential thermal analysis and the two decomposition peaks were observed. The high temperature peak was found to shift to lower temperatures, but the corresponding shift in the low temperature peak was smaller due to the effect of nanometer metal powders. Results shows that Cu and NiCu nanopowders decreased both the high and low decomposition temperature, while Ni and Al nanopowders just decreased the high decomposition temperature and increased the low decomposition temperature. Metal micron‐sized powders show catalytic effects on the thermal decomposition of AP, but their effects are less than that of nanometer metal powders. With the increase in content, nanometer metal powders enhanced their catalytic effect on the high temperature decomposition of AP, however their effect was weakened on the low temperature decomposition.     

Experimental Study of the Effect of Metal Nanopowders on the Decomposition of HMX,AP and AN

The effect of metal nanopowders (Al, Fe, W, Ni, Cu, and Cu‐Ni alloys) on the decomposition of energetic materials (HMX, AP, and AN) with DTA–TGA method was studied and it was found that the catalytic action appears in the case of Cu‐Ni nanopowders with the three studied energetic materials. The temperature of decomposition of energetic materials with the addition of metal nanopowders could be lowered by 82 °C for AN, 161 °C for AP, and 96 °C for HMX. The reaction mechanism of metal nanopowders enhancing the decomposition of energetic materials is discussed.     

Preparation of Cu/CNT Composite Particles and Catalytic Performance on Thermal Decomposition of Ammonium Perchlorate

Composite particles of carbon nanotubes (CNTs) and Cu were prepared by a chemical reduction method. Characterization of Cu/CNT composite particles was performed by TEM, SEM, FT‐IR, XRD, XPS, AAS, DTA and EDS. The results show that the surface of CNTs is covered by Cu particles, and that the diameter of Cu/CNT composite particles gets larger than that of CNTs. Furthermore, in the presence of Cu/CNT composite particles, the peak temperature of the high‐temperature decomposition of ammonium perchlorate (AP) decreased by 126.3 °C, and the peak of the low‐temperature decomposition disappeared. Compared with a sample of simply mixed Cu and CNTs, the peak temperature of the high‐temperature decomposition of AP‐Cu/CNTs composite particles decreased by 11.4 °C. Compared with Cu, the peak temperature of the high‐temperature decomposition of AP‐Cu/CNT composite particles decreased by 20.9 °C. This work shows that the catalytic performance of Cu on the thermal decomposition of AP can be improved by compounding with CNTs.     

铁酸铋/石墨烯纳米复合材料的制备及其对高氯酸铵热分解的催化作用

为了提高纳米复合金属氧化物对高氯酸铵(AP)热分解的催化作用,以Bi(NO₃)₃·5H₂O、Fe(NO₃)₃·9H₂O和GO为前驱体,采用水热法制备了铁酸铋/石墨烯(BiFeO₃/rGO)纳米复合材料;利用XRD、FT-IR、XPS、TGA、SEM和TEM等对所制备样品的结构、粒径及形貌进行了表征;采用差热分析研究了不同添加量的BiFeO₃/rGO纳米复合材料对AP热分解过程的影响,分析了BiFeO₃/rGO对AP热分解的催化机理及其对AP热分解动力学的影响。结果表明,rGO的引入有效阻止了纳米BiFeO₃颗粒的团聚,大大增加了比表面积;当BiFeO₃/rGO纳米复合材料的质量分数为4%时,AP的高温分解峰降低最多,达167℃,表观分解热增加了1631J/g,达2518J/g,表观活化能从172.07kJ/mol降低至128.35kJ/mol,表明所制备的BiFeO₃/rGO纳米复合材料能有效催化AP的热分解。     

储氢合金/AP/HTPB推进剂的热分解性能

采用TG-DTG、DSC以及动力学分析方法研究了储氢合金/AP/HTPB推进剂的热分解性能。结果表明,相对于Al/AP/HTPB推进剂,储氢合金/AP/HTPB推进剂的热分解温度降低,放热量提高;A20/AP/HTPB推进剂的凝聚相反应程度提高2.44%,第二、三温区的热分解活化能(Kissinger法)分别降低4.06%和22.63%;A30/AP/HTPB推进剂的凝聚相反应程度提高10.61%,第二、三温区的热分解活化能(Kissinger法)分别降低30.89%和38.87%。储氢合金对AP/HTPB推进剂的热分解有催化作用,并且该催化作用随着储氢合金中Mg0.45Ni0.05B0.5Hx含量的增加而增强。     

Effect of Zn Powders on the Thermal Decomposition of Ammonium Perchlorate

In this paper, the catalytic effect of Zn nanopowders on thermal decomposition of ammonium perchlorate (AP) as well as those of Zn micropowders has been investigated using differential thermal analysis (DTA). The results show that both nanometer and micrometer Zn powders show similar excellent catalytic effect on the decomposition of AP, while the total heat releases of AP added by Zn nanopowders are generally higher than those of AP added by Zn micropowders. In addition, an attempt has been made to explain the observed results with the help of theoretical considerations and data generated during this work.     

纳米金属钴粒子的制备及对高氯酸铵热分解的影响

The monodispersed Co nanoparticles were successfully prepared by means of hydrogen plasma method in inert atmosphere. The particle size, specific surface area, crystal structure and morphology of the samples were characterized by transmission electron microscopy （TEM）, BET equation, X-ray diffraction （XRD）, and the corresponding selected area electron diffraction （SAED）. The catalytic effect of Co nanoparticles on the decomposition of ammonium perchlorate （AP） was investigated by differential thermal analyzer （DTA）. Compared with the thermal decomposition of pure AP, the addition of Co nanoparticles （2%-10%, by mass） decreases the decomposition temperature of AP by 145.01-155.72℃. Compared with Co3O4 nano-particles and microsized Co particles, the catalytic effect of Co nanoparticles for AP is stronger. Such effect is attributed to the large specific surface area and its interaction of Co with decomposition intermediate gases. The present work provides useful information for the application of Co nanoparficles in the AP-based propellant.     

The catalytic effect of nanosized MgO on the decomposition of ammonium perchlorate

MgO nanoparticles with an average size of 30 nm were prepared by a traditional sol-gel method using magnesium chloride and NaOH aqueous solution as the raw materials. X-ray diffraction (XRD) and transmission electron microscopy (TEM) were used to characterize the products. The catalytic effect of the MgO prepared on the decomposition of ammonium perchlorate (AP) was investigated by differential thermal analysis (DTA). The results indicate that MgO nanoparticles have a good dispersibility and a uniform crystallite size, also have an intense catalytic effect on the decomposition of AP comparing with commercial product.     

Catalytic hydrogenation of anthracene in ethanol

The results of the hydrogenation of anthracene in ethanol in the presence of different catalysts (the nanosized powders of Fe, Cu, and β-FeOOH and Ni and Fe supported on carbon microspheres) are reported. The greatest catalytic effect was observed upon the introduction of 1.5% Fe nanopowder.