NiO with different morphologies were prepared by precipitation method and then the NiO/γ-Al2O3 catalysts were prepared from NiO and γ-Al2O3 by grind-mixing method. These catalysts were characterized by means of TEM, XRD and H2-TPR techniques. TEM images show that the morphologies of three NiO phases ( aNiO, b-NiO and c-NiO) obtained are in the shape of rod, granule and sheet, respectively. H2-TPR profiles show that the oxidabilities of these catalysts are in the order of b-NiO/γ-Al2O3 ＜ a-NiO/γ-Al2O3 ＜ c-NiO/γ-Al2O3.XRD patterns show that the crystalline sizes of Ni in these catalysts after reduction are in the order of b-Ni ＞ a-Ni ＞ c-Ni. CO methanation was carried out over the Ni/γ-Al2O3 catalysts in a continuous flow fixed-bed reactor and the effects of mixing method and morphology of active species on the catalysts perforce were investigated. It is found that the catalyst prepared from grind-mixing exhibits higher activity and stability than that obtained from simple-mixing. The catalytic activities of these catalysts with different morphologies for CO methanation follow the order of c-Ni/γ-Al2O3＞ a-Ni/γ-Al2O3＞ b-Ni/γ-Al2O3. Over the c-Ni/γ-Al2O3 catalyst (wNi = 15％ ) under the conditions of atmospheric pressure, 593 K and a space velocity of 2 500 h-1 , the conversion of CO and the selectivity to CH4 reach 99.63％ and 90.80％, respectively.%采用沉淀法分别以乙二醇、水、乙二醇-聚乙二醇600为修饰剂,制备了形貌分别为棒状(a-NiO)、粒状(b-NiO)和片状(c-NiO)结构的NiO催化剂,然后和γ-Al2O3通过研混法制得NiO/γ-Al2O3催化剂.采用XRD、TEM及H2-TPR等技术手段对催化剂进行了表征.TEM观察NiO的形貌分别为棒状、粒状和片状.H2-TPR结果表明,NiO/γ-Al2O3催化剂的氧化中心数量顺序为b-NiO/γ-Al2O3＜a-NiO/γ-Al2O3＜c-NiO/γ-Al2O3.XRD结果表明,NiO/γ-Al2O3催化剂还原后的Ni晶粒尺寸大小为b-Ni＞a-Ni＞c-Ni.在连续流动固定床反应装置上考察了Ni/γ-Al2O3对CO甲烷化反应的催化活性,研究了混合方法和形貌对CO甲烷化反应的影响.结果表明,研混法制得催化剂的活性及稳定性较好.催化剂形貌对CO甲烷化反应的催化活性顺序为c-Ni/γ-Al2O3＞a-Ni/γ-Al2O3＞b-Ni/γ-Al2O3,常压、593 K和2 500 h-1反应条件下,wNi为15%c-Ni/γ-Al2O3催化CO合成CH4选择性及CO转化率分别达90.80%和99.63%.
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