Ni/Al_2O_3催化剂的制备及其催化NH_3分解性能研究

Preparation of Ni/Al_2O_3 catalyst and its catalytic performance in ammonia decomposition

以Ni(NO_3)_2·6H_2O、Al(NO_3)_3·9H_2O和Na_2CO_3为原料,采用共沉淀法制备了不同摩尔比的Ni/Al_2O_3催化剂。并用单点BET、XRD、TPR、TPSR以及化学吸附方法对催化剂的结构及氨分解反应的催化活性进行表征。结果表明,与Al_2O_3载体复合的NiO材料的催化活性明显高于纯NiO的催化活性。镍的摩尔分数为20%相对应的NiAl催化剂的Ni的分散度最大并且催化活性最高。当9. 7%NH_3/He混合气流速控制在10 m L/min且反应温度为600℃时,该材料的氨转化率为96. 1%。

A series of Ni/Al2O3 catalysts with different molar ratios are prepared by co-precipitation method using Ni( NO3)2·6H2O,Al(NO3)3·9H2O and Na2CO3 as raw materials. Single-point BET,XRD,TPR,TPSR and H2-chemisorption are used to characterize the structure of the prepared catalyst and its catalytic activity in ammonia decomposition.The results indicate that the catalytic activity of the Ni O material composited with Al2O3 supporter is significantly higher than that of pure Ni O catalysts. The catalyst containing 20% of nickel in molar has the largest dispersion of Ni and the highest catalytic activity and the ammonia conversion rate over this catalyst can reach 96. 1%when the flow rate of 9. 7% NH3/He mixture gas is controlled at 10 m L·min-1 and the reaction temperature is set at 600℃.