六铝酸盐催化剂上甲烷与二氧化碳重整反应的研究

合成了具有磁铅石结构的Sr_1-xLaxNiAl₁₁O₁₉系列催化剂,并用XRD、UV-DRS、H₂-O₂滴定及Py-IR等方法对其体相及表面性质进行了表征,考察了甲烷与二氧化碳重整反应活性及积炭性.结果表明,La³⁺离子能够同晶取代Sr²⁺离子进入催化剂晶格内部,使催化剂的结晶度提高,还原性降低,同时降低了催化剂表面的酸性,有助于提高催化剂的抗积炭能力.

Studies of Methane Reforming with Carbon Dioxide on Hexaaluminates

In this paper, a series of Sr 1- x La x NiAl 11 O 19 catalysts were synthesized and their chemical and physical properties were investigated by XRD, UV DRS, H 2 O 2 titration, TPR and Py IR techniques. The experimental results show that the Sr 1- x La x NiAl 11 O 19 catalysts have a magnetoplumbite structure and Ni ion is shared between tetrahedral and octahedral sites of the spinel blocks, and the amount of nickel ions in the tetrahedral environment increases with the increase of x value in Sr 1- x La x NiAl 11 O 19 . The TPR study revealed that the reducibility of the series of the catalysts depends strongly on the substitution value x , that is, a low temperature peak appears for samples without substitution, in case of samples with x =1 high temperature peak appears, and for samples with 0< x <1, both low and high temperature peaks appear. The partial substitution of Sr 2+ by La 3+ shows no significant effect on the catalytic activity for reforming reaction due to the similar dispersion of Ni particle. Whereas, the substitution has a great effect on the acidity of catalyst, the number of acidic sites and amount of the carbon deposition on the catalyst surface. So it is evident that carbon deposition in carbon dioxide reforming of methane can be suppressed by decreasing the acidity of the complex oxides catalysts.