Pd-CeO2-Al2O3对烟气中多环芳烃的催化氧化性能研

Abstract

<dd>采用浸渍法制备了不同负载量及不同钯铈比（Pd：Ce）的Pd/CeO2-Al2O3催化剂,并结合XRD、BET、SEM、O2-TPD和H2-TPR等方法对催化剂的性质进行了表征,研究了所制备的催化剂对燃煤烟气中多环芳烃（PAHs）的催化转化效率.XRD和SEM结果表明,Ce和Pd在Al2O3表面呈高度分散状态,有利于PAHs的催化氧化.BET测试表明,Ce的引入改变了催化剂表面孔径结构,提高其比表面积.O2-TPD和H2-TPR测试表明,适当钯铈比条件下制备的催化剂有较强的储氧能力和活性.催化氧化实验结果表明,所制备的Pd/CeO2-Al2O3催化剂对PAHs具有较高的转化效率,其平均转化率均在80%以上,且PAHs的毒性当量显著降低,钯铈比对PAHs的催化氧化性能影响较大,当催化剂的钯铈比为1：1时,PAHs的转化率最高,可达90%以上.</dd>Pd/CeO2-A1203 catalysts with various loading percentages and different Pd-to-Ce ratios were prepared by impregnation method. The physicochemical properties were characterized with XRD, BET, SEM, O2-TPD and H2-TPR, and their catalytic performances were evaluated by the conversion efficiency of PAHs in flue gas. The results of XRD and SEM demonstrated that Ce and Pd were highly dispersed, which was in favor of the catalytic oxidation of PAHs. BET tests showed that the introduction of Ce changed the pore structure of catalyst and improved the specific surface area. The results of 02-TPD and H2-TPR confirmed that the catalysts prepared in the appropriate Pd:Ce had strong oxygen storage capacity and activity. The experimental results of catalytic oxidation of PAl-Is showed that the as-prepared Pd/CeO2-Al2O3 possessed high catalytic efficiency with the average conversion efficiency of above 80% , and the TEQ ( Toxic Equivalent Quantity) of PAHs decreased remarkably after the catalytic reaction. The ratio of Pd- to-Ce influenced the oxidation of PAHs greatly, and the conversion efficiency of PAHs could reach more than 90% when Pd:Ce equaled to 1 : 1