ZrO2在Rh/γ-Al2O3催化剂中对NO催化还原反应的作用

摘要

The effect of ZrO2 additives on Rh/γ-Al2O3 was studied.The TPR,XRD,BET surface area and the catalysts activity of NO+C2H4 and NO+C2H4+O2 reactions were measured for the catalysts with variety of crystal phases and doping manners of ZrO2 It is found that the ZrO2 possesses the ability of depressing the interaction between Rh3+ and γ-Al2O3 and retarding the phase transition of γ-Al2O3 to some extent.The reaction activity of NO+C2H4 is pronounced enhanced during ZrO2 doped onto the Rh/γ-Al2O3 after aging at 850℃ in atmosphere for 2h than that of the Rh/γ-Al2O3,while the activity of SCR for the samples is low and the sample containing ZrO2 is lower than that of the Rh/γ-Al2O3.It implicates that the reaction mechanism is quite different between NO+C2H4 and NO+C2H4+O2.The Competitive full oxidation of C2H4 promoting by ZrO2 is suggested.%测定了含ZrO2的Rh/γ-Al2O3催化剂上NO+C2H4和NO+C2H4+O2的反应活性，并应用TPR、XRD、BET比表面等表征了ZrO2的加入方式和晶型对Rh/γ-Al2O3催化剂活性和结构的影响。结果表明，ZrO2的加入一定程度地抑制了Rh3+与γ-Al2O3之间的相互作用和γ-Al2O3的相变，提高了催化剂的热稳定性，明显提高了850℃老化样品的NO+C2H4反应活性。对于NO+C2H4+O2反应，含ZrO2样品的选择还原活性却较低，表明反应机理不同，而且ZrO2对C2H4的深度氧化有促进作用，但老化后活性下降幅度比不含ZrO2的样品小。