氮化SBA-16负载镍基催化剂的制备及其对甲烷二氧化碳重整反应的催化性能

通过软模板法合成了SBA-16分子筛,采用高温氨气氮化的方法使有序介孔硅材料中的氧原子部分被氮原子取代,得到氮化的SBA-16载体(SBA-16-N)。采用满孔浸渍法制备了镍基催化剂,并将制得的Ni/SBA-16和Ni/SBA-16-N催化剂用于甲烷二氧化碳重整反应。通过透射电镜、氮气物理吸附、X射线衍射、X射线光电子能谱和二氧化碳程序升温脱附等手段研究了载体和催化剂的结构,并利用热重分析对反应之后回收催化剂进行了表征。结果表明,高温氮化后的分子筛中掺入了氮元素,增加了载体的碱性,改善了载体对反应气体的吸附活化能力,增强了载体与金属之间的相互作用,从而提高了催化剂的活性和抗积炭性能。

Synthesis of Ni-based catalysts supported on nitrogen-incorporated SBA-16 and their catalytic performance in the reforming of methane with carbon dioxide

SBA-16 molecular sieve was synthesized by soft template method and modified with ammonia under high temperature to obtain the nitrogen-incorporated SBA-16 (SBA-16-N); with SBA-16 and SBA-16-N as the supports, nickel based catalysts (Ni/SBA-16 and Ni/SBA-16-N) were prepared by the incipient impregnation method. The related supports and Ni-based catalysts were characterized by transmission electron microscope, X-ray photoelectron spectroscopy, nitrogen physisorption, carbon dioxide temperature programmed desorption, X-ray diffraction and thermogravimetric analysis; the catalytic performance of Ni/SBA-16 and Ni/SBA-16-N in the reforming of methane with carbon dioxide was comparatively investigated under 500–800°C. The results indicate that after the nitriding modification, the Ni/SBA-16-N catalyst exhibits much higher activity in methane reforming with CO₂ and higher selectivity to syngas than the Ni/SBA-16 catalyst without nitridation treatment. During the nitriding modification at high temperature, O atoms in the SBA-16 skeleton are partially replaced by N atoms, which can strengthen the support basicity and the interaction between the support and the nickel nanoparticles. All these may promote the dispersion of nickel nanoparticles on SBA-16-N and the adsorption of CO₂ on Ni/SBA-16-N, leading to the improvement of the activity and stability of the Ni/SBA-16-N catalysts in methane reforming with carbon dioxide.