低温下花球状Ni/CeO_2催化剂上甲烷水蒸气重整制氢研究

Low temperature methane steam reforming over flowerlike NiO/CeO_2 catalyst

利用水热法制备花状CeO_2,采用浸渍热分解法制备NiO/CeO_2催化剂,NiO纳米颗粒均匀地分布在CeO_2花瓣上,达到了高度的分散,增加了甲烷和水脱氢作用的活性位点。通过XRD、SEM对催化剂进行表征。甲烷水蒸气重整结果表明,该催化剂低温下表现了良好的活性,较高的转化率,较好的稳定性和理想的抗积炭能力。催化剂稳定性超过300 h,550℃时甲烷转化率达到95%。不同水碳比下的催化性能测试结果表明,1.5～2.5的低水碳比为该催化剂的理想范围。因此,该催化剂在低温甲烷水蒸气重整制氢上表现良好,是一种很具潜力的催化剂。

Flower like microsphere CeO_2 samples are prepared by the hydrothermal method. The NiO/CeO_2 catalyst is then prepared by impregnation and nano-sized nickel oxide particles are highly dispersed on flower like cerium oxide microspheres to increase the active sites for simultaneous dehydrogenation of methane and water molecules. The structure of catalyst is characterized by X-ray diffraction（ XRD） and scanning electronic microscope（ SEM）. The methane steam reforming results show that this special catalyst NiO/CeO_2 has high activity and stability,and improves the resistance of carbon deposition catalyst greatly. The stability of the catalysts can reach more than 300 hours. The conversation of methane under 550℃ is about 95%. The influence of the ratio of steam and carbon on activity and selectivity of catalyst is also carried out. The result inciates that 1. 5- 2. 5 of the ratio of steam to carbon is an ideal choice. This special catalyst NiO/CeO_2 is a potential methane steam reforming catalyst.