本文以蜂窝状堇青石陶瓷为催化剂载体,用分步浸渍法制备了挥发性有机废气(VOCs)净化用Pd—Ni/La—Ce-Zr-Al2O3/堇青石催化剂,考察了Ni助催化剂对单钯型VOCs净化催化剂性能的影响,并用Hr-TPR、比表面、XRD、SEM等手段对催化剂进行了表征。研究表明,Nj的加入明显提高了催化剂的低温活性和热稳定性,经过800℃焙烧的Pd—Ni/La—Ce—Zr-Al2O3/堇青石(mpd.mNi=3:20)催化剂的催化性能明显优于Pd/La-Ce—Zr-Al23O堇青石催化剂,甲苯起燃温度下降约25℃,经1000℃高温处理后,仍能保持优良的催化性能。Ni的加入使Pd催化剂性能提高的原因应归结于活性组分分散度的提高和钯、镍与载体之间存在的强相互作用。
Pd-Ni / La-Ce-Zr-Al2O3 cordierite monolith catalyst for destractive removal of volatile organic gases was prepared by the step-impregnation method and characterized by H2-TPR, automatic N2 adsorption and desorption, XRD and SEM technologies, and the promotion of Ni on the performance of Pd-only combustion catalyst was investigated. The results show that the presence of Ni improves obviously the catalytic activity and thermal stability of the Pd-only combustion catalyst. The Pd-Ni/La-Ce-Zr-Al2O3/cordierite monolith catalyst (mpdmNi=3:20) calcined at 800 ℃ performed much better than Pd/La-Ce-Zr-Al2O3/cordierite monolith catalyst for the deep oxidation of toluene, for example, the light-off temperature of toluene over Pd-Ni catalyst is lower -25 ℃ than that over Pdonly catalyst, and it has high thermal stability even after pre-treated at 1 000℃. Addition of Ni promotes the catalytic activity and thermal stability of the supported Pd-only catalyst by active components highly dispersed on the surface of catalyst and strong metal-support interactions between palladium, nickel and the support.