原位共沉淀法制备Ni-Mg-Al-LDHs/γ-Al_2O_3催化前驱体在甲烷二氧化碳重整反应体系中的性能评价（英文）

In-situ Co-Precipitation of Ni-Mg-Al-LDH Catalytic Precursor on γ-Al_2O_3 for Dry Reforming of Methane: Synthesis and Evaluation

通过原位共沉淀的方法在γ-Al2O3表面上合成了Ni-Mg-Al-LDHs(水滑石),合成的Ni-Mg-Al-LDHs/γ-Al2O3作为催化前驱体经过不同的热处理还原方式得到催化剂Cat-1、Cat-2和Cat-3.用X射线衍射(XRD)、透射电镜(TEM)、N2吸附-脱附测试(BET)以及热重-差热分析(TG-DTA)对催化剂的形貌结构和抗积碳能力进行了表征测试;通过甲烷二氧化碳重整反应体系对催化剂的反应活性和稳定性进行了评价.结果表明催化剂前驱体的预处理方式对催化剂的反应性能具有较大的影响.Ni-Mg-Al-LDHs/γ-Al2O3直接经过H2/Ar常压高频冷等离子体炬的分解还原所获得的催化剂Cat-3表现出了最佳的催化活性和稳定性.TEM表征表明催化活性组分在Cat-3上的分散性更好,颗粒粒径更小.BET结果证明Cat-3具备较大的比表面积(195.8 m2?g-1).Ni-Mg-Al水滑石的结构赋予了催化剂活性组分在载体γ-Al2O3上均匀的分散性,同时常压高频冷等离体炬对催化剂的表面结构以及活性组分的还原具有进一步的优化作用,两者的协同作用使Ni-Mg-Al-LDHs/γ-Al2O3在甲烷二氧化碳反应体系中具备优良的催化活性和抗积碳性能.

A series of novel catalysts derived from Ni-Mg-Al-LDHs（LDHs： layered double hydroxides） were synthesized in-situ on γ-Al2O3 and evaluated in CO2 reforming of CH4（dry reforming of methane, DRM） reaction system. The catalytic precursors were decomposed and reduced by calcination and an atmospheric plasma technique, respectively. Activity and stability tests showed that the catalytic properties were greatly affected by the pretreatment method. The best catalytic performance was obtained with the catalyst that was directly reduced and decomposed using an atmospheric H2/Ar plasma jet. Compared with the pure LDH precursor, NiMg-Al-LDHs/γ-Al2O3 had much greater mechanical strength, because of the γ-Al2O3 support. This feature extends the long lifetime of catalyst at high temperatures. X-ray diffraction（XRD）, transmission electron microscopy（TEM）, N2-adsorption-desorption, and thermogravimetry-differential thermal analysis（TG-DTA） results showedthat the excellent catalytic performance was based on the small particle size and uniform dispersion of active Ni crystals, as well as the high mechanical strength and large specific surface area of the catalyst.