水蒸汽对Ni/CeO2-ZrO2-Al2O3催化剂上CO2+CH4重整反应的影响

用水热合成法制备了Ni/CeO2 ZrO2 Al2 O3 催化剂 .进行了添加和不添加水蒸汽的CH4 +CO2 催化重整反应 ,测试了活性和稳定性 ,测量了积碳量 ,并用XAFS手段测试了催化剂Ni的K吸收边 .结果表明 ,在反应过程中有CeAlO3 的生成 ,但积碳是无水蒸汽添加的反应活性降低的原因 .反应气中添加水蒸汽能够减少积碳 ,从而提高催化反应的稳定性 .由于碳原子插入Ni晶格 ,无水蒸汽反应后的最近邻Ni Ni配位数有较大幅度的减少 .添加了水蒸汽的反应 ,最近邻Ni Ni配位数比反应前减少幅度小 ,这主要是由于在反应气中添加水蒸汽减少了积碳 ,从而稳定催化剂中活性Ni金属结构的结果

Influence of CO2 Reforming of CH4 Reaction Performance by Adding Vapor on Ni/CeO2-ZrO2-Al2O3 Catalyst

The Ni/CeO 2-ZrO 2-Al 2O 3 catalyst was prep ar ed with the hydrothermal method. The catalytic performance for the CO 2 reformi ng of CH 4 reaction with or without small amount of steam was tested and the am ount of coke deposition was measured. The XAFS of Ni K-edge was attained. The r esults show that the formation of CeAlO 3 occurs in reaction, but the coke depo sition is responsible for the deactivation of the catalyst. The addition of stea m into feed gas can decrease the amount of coke deposition, and promote the stab ility. Due to the carbon atom penetration into the Ni lattice, for the catalyst sample after reaction without the addition of steam into feed gas, the coordinat ion number of the first Ni-Ni shell decreases sharply. For the catalyst sample after reaction with the addition of steam in feed gas, the coordination numbers of the first Ni-Ni shell decrease slightly. It is due to the addition of steam into feed gas, which can suppress the coke formation and maintain the metallic s tructure of active Ni metal.