高性能Ni基甲烷重整催化新材料制备及应用研究

发布时间：2018-07-03 00:52

本文选题：甲烷重整制氢 + Ni-Co合金催化剂　；参考：《南昌大学》2015年硕士论文

【摘要】：氢气是一种绿色能源,能量密度大,燃烧后产物为水,不仅不会对环境造成污染,还有可能替代石化燃料解决能源危机问题。因此,氢气在21世纪能源舞台上将扮演重要的角色。目前,甲烷水蒸汽重整是最有效和可行的制氢方法,且已大规模工业化。Ni基催化剂因价格低廉、储量丰富且活性高,已被广泛应用于甲烷重整。但该类催化剂易积碳,Ni活性中心高温下易烧结,导致催化剂失活。因此,为降低制氢成本,促进氢气作为绿色能源推广,有必要研发具有更高抗烧结能力和抗积碳性能的催化剂。本论文针对该目标展开研究,主要结果如下:首先,使用共浸渍方法制备一系列不同Co含量的Ni-Co/γ-Al2O3双金属催化剂,其中Ni的质量百分比为12%,并将其用于甲烷水蒸气重整制氢反应。结果表明,Co的添加虽然使得催化剂低温活性略有降低,却很好地提高了Ni/Al2O3催化剂的抗积碳性能和反应稳定性。XPS和TEM结果证明Ni和Co之间存在强相互作用。还原后催化剂的XRD和HAADF-STEM mapping结果提供了直接的证据表明Ni和Co之间形成了Ni-Co合金。该合金的形成可有效覆盖部分低配位的活泼Ni中心,降低催化剂对C-H键的活化能力,抑制C-C键的形成,因而有效地抑制了催化剂在反应过程中积碳。其次,分别合成了介孔Al-SBA-15和球形树枝状KCC-1载体,利用去离子水和乙二醇作为溶剂,采用浸渍法制备了7%Ni/Al-SBA-15和Ni/KCC-1等催化剂。结果表明,用乙二醇作为溶剂,结合上述两种不同形貌介孔载体所制备的催化剂,具备很高的活性、稳定性和优良的抗积碳性能。XRD和TEM测试结果证明,在这些催化剂上,Ni活性组分的粒度可被孔道限域在5 nm以下,从而抑制了反应过程中Ni的高温烧结,有效地提高了催化剂的活性和抗积碳性能。
[Abstract]:Hydrogen is a kind of green energy with high energy density and water after combustion. It not only can not pollute the environment, but also can replace fossil fuels to solve the problem of energy crisis. Therefore, hydrogen will play an important role in the 21 st century energy stage. At present, steam reforming of methane is the most effective and feasible method for hydrogen production, and has been widely used in methane reforming because of its low price, rich reserves and high activity. But this kind of catalyst is easy to be sintered at high temperature, which leads to the deactivation of the catalyst. Therefore, in order to reduce the cost of hydrogen production and promote the promotion of hydrogen as a green energy, it is necessary to develop catalysts with higher sintering resistance and carbon deposition resistance. The main results are as follows: firstly, a series of Ni-Co- / 纬 -Al _ 2O _ 3 bimetallic catalysts with different Co contents were prepared by co-impregnation method, in which the mass percentage of Ni was 12%, which was used for hydrogen production by steam reforming of methane. The results showed that the low temperature activity of Ni / Al _ 2O _ 3 catalyst decreased slightly with the addition of Co, but the carbonization resistance and reaction stability of Ni / Al _ 2O _ 3 catalyst were improved. The results of XPS and TEM showed that there was a strong interaction between Ni and Co. The results of XRD and HAADF-STEM mapping showed that Ni-Co alloy was formed between Ni and Co. The formation of the alloy can effectively cover some active Ni centers with low coordination position, reduce the activation ability of the catalyst to C-H bond, and inhibit the formation of C-C bond, thus effectively restrain the carbon deposition in the reaction process of the catalyst. Secondly, mesoporous Al-SBA-15 and spherical dendritic KCC-1 support were synthesized, and 7Ni- / Al-SBA-15 and Ni- / KCC-1 catalysts were prepared by impregnation method using deionized water and ethylene glycol as solvents. The results show that the catalysts prepared by using ethylene glycol as solvent and the mesoporous carriers with different morphology have high activity, stability, and excellent resistance to carbon deposition. XRD and TEM results show that the catalysts have excellent resistance to carbon deposition. The particle size of the active component of Ni on these catalysts can be limited to 5 nm by the pore channel, which can inhibit the sintering of Ni at high temperature during the reaction, and effectively improve the activity and the resistance to carbon deposition of the catalyst.
【学位授予单位】：南昌大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：O643.36;TQ116.2

【参考文献】