镧钡改性氧化铝负载钯、铑的催化活性研究

采用纯γ-氧化铝和改性氧化铝（2.5%La2.5%Ba/Al2O3）为担体，经550 ℃，950 ℃不同温度煅烧后分别负载钯、铑，制备成系列催化活性材料，通过贵金属分散度分析、TPR氧化还原特性分析，研究了氧化铝制备条件对催化活性的影响。结果表明，改性氧化铝上的贵金属分散性优于纯γ-氧化铝，Rh3⁺与2.5%La2.5%Ba/Al₂O₃间的相互作用强于Pd²⁺，从而具有更高的分散度；钯在高温处理后的2.5%La2.5%Ba/Al₂O₃上的分散性更优，铑则相反。通过TPR还原特性分析认为，贵金属在950 ℃煅烧后的2.5%La2.5%Ba/Al₂O₃上的低温还原活性更佳，钯与2.5%La2.5%Ba/Al₂O₃结合的低温还原活性优于铑。

Study on catalytic activity of La/Ba-modified Al2O3 supported Pd and Rh catalyst

Pure γ-Al₂O₃and modified alumina (2.5%La2.5%Ba/Al2O3) were calcined at 550 ℃ and 950 ℃,on which Pd and Rh were respectively loaded to form series catalytic materials.By analysis of precious metal dispersity and TPR experiment,the effect of alumina preparation conditions on catalytic activity were studied.Results showed that the precious metal dispersity on 2.5%La2.5%Ba/Al₂O₃ was superior to on pureγ-Al₂O₃,interaction of 2.5%La2.5%Ba/Al₂O₃ with Rh³⁺ was stronger than that of with Pd2+so as to have better dispersity;Pd on the high temperature calcined 2.5%La2.5%Ba/Al₂O₃ had better dispersity and Rh was to the contrary.TPR results showed that precious metals on calcined 2.5%La2.5%Ba/Al₂O₃at 950 ℃ had better lowtemperature reduction activity,and lowtemperature reduction activity of 2.5%La2.5%Ba/Al₂O₃-Pd was higher than that of 2.5%La2.5%Ba/Al₂O₃-Rh.