密闭空间CO消除的Pd／Al2O3催化剂合成及其催化性能研究

Synthesis of Pd/Al_2O_3 catalysts and their catalytic performance for carbon monoxide elimination in confined space

采用浸渍法制备不同PdCl_2含量的贵金属催化剂,并对反应前后催化剂进行傅里叶红外和物理结构表征。结果表明,PdCl_2质量分数为3%的催化剂活性最高,可在70℃实现低浓度CO的完全转化。反应后,催化剂表面没有明显变化,催化剂比表面积增大,孔容及平均孔径呈减小趋势。研究进口CO浓度和空速对CO转化率的影响,结果表明,在一定浓度范围,提高进口CO浓度对CO转化率没有影响,浓度超过1 000×10^(-6)时,CO转化率下降;空速升高,CO转化率下降,温度越低,空速对CO转化率影响越大。

The noble metal catalysts with different PdCl2 contents were prepared by impregnation method. The catalysts before and after reaction were characterized by FTIR and N2 physical adsorption. The results of activity measurement revealed that the catalyst with 3wt% PdCl2 had the highest activity and could achieve the total conversion of low concentration CO at 70℃. No change of the surface of the catalyst after reaction was observed according to the results of IR characterization. The results of N2 physical adsorption revealed that the specific surface area of the catalysts increased, and the pore volume and the mean pore size showed the trend of decrease. The influence of inlet CO concentration and GHSV on CO conversion was investigated. The results indicated that within certain concentration, the increase of inlet CO concentration had no influence on CO conversion; whereas CO concentration exceeded 1 000 × 10^-6 or the GHSV was increased, CO conversion decreased. The lower the temperature, the greater the effects of space velocity on CO conversion.