摘要
以NH_4HCO_3为造孔剂通过一步水热法成功合成了介孔型单晶NiAl_2O_4纳米棒,并考察了不同反应条件对NiAl_2O_4形貌的影响.实验结果表明反应时间、反应物浓度、NH_4HCO_3加入量对产物形貌具有关键作用.用透射电子显微镜(TEM),高分辨透射电子显微镜(HRTEM),扫描电子显微镜(SEM)和X射线衍射仪(XRD)对NiAl_2O_4纳米棒的形貌、结构和组成进行表征,并用氮气吸附-脱附法对其比表面积和孔径分布进行了研究.以介孔型NiAl_2O_4纳米棒为催化剂,在固定床反应器上对甲苯进行催化实验,结果表明当水炭摩尔比为1.0、反应温度为700℃时,400 min反应时间内甲苯平均转化率高达86.5%,并具有较好的反应稳定性.比较了直接沉淀法制备的纳米颗粒作为催化剂在甲苯氢化催化裂解中的催化性能.结果表明水热法制备的棒状NiAl_2O_4催化剂比不用水热制备的催化剂催化活性要好.初步探讨了介孔型NiAl_2O_4纳米棒的可能形成机理.
Mesoporous single-crystalline NiAl2O4 nanorods were successfully synthesized by a one-step hydrothermal method using a pore-forming agent （NH4HCO3）. A series of controlled experiments were also carried out to better understand the formation mechanism of NiAl2O4 nanorods. The experimental results indicate that the reaction time, reactant concentration and the amount of NH4HCO3 play an important role in determining the morphology. The morphology, structure and composition of the nanorods were investigated using transmission electron microscopy, high resolution transmission electron microscopy, scanning electron microscopy and X-ray diffraction. The specific surface area and pore-size distribution of the obtained product was determined by nitrogen adsorption-desorption measurements. NiAl2O4 nanorods have a high Brunauer-Emmett-Teller surface area and good porosity properties. The catalytic performance of the NiAl2O4 nanorods during toluene hydrocracking was investigated using a fixed bed reactor. After the toluene catalytic reactions over 400 rain at a water stream/carbon molar ratio （H2O/C） of 1.0 with a reaction temperature of 700℃ the average conversion efficiency of toluene was about 86.5%. Compared to the NiAl2O4 nanoparticles prepared by alkaline precipitation, the mesoporous NiAl2O4 nanorods exhibited higher catalytic activity and stability during toluene hydrocracking. A possible formation mechanism for the mesoporous NiAl2o4 nanorods is proposed and discussed.
出处
《物理化学学报》
SCIE
CAS
CSCD
北大核心
2011年第7期1743-1750,共8页
Acta Physico-Chimica Sinica
基金
国家自然科学基金(20973108)
上海教委(11ZZ83)
上海市重点学科建设(J50101)
上海大中创新基金(A.10-0101-09-023)资助项目~~
