银赋存形态对钴酸镧催化燃烧碳烟性能影响的研究

Study on the effect of Ag existence form in LaCoO_(3)on the soot catalytic combustion

控制柴油车尾气排放的关键是提高碳烟催化燃烧的低温活性。采用溶胶-凝胶法和浸渍法合成不同银赋存形态的钴酸镧(LCO),考察不同银赋存形态对碳烟催化燃烧性能的制约机制。结果表明,当煅烧温度为250、450℃时,LCO表面的银分别为Ag_(2)O和Ag^(0);当煅烧温度为700℃时Ag^(0)与Ag^(+)形态共存。煅烧温度为250℃、采用溶胶-凝胶法和浸渍法合成的催化剂表现出最佳的催化性能,归因于Ag_(2)O与LCO载体之间的相互作用。

The key to control the exhaust emission of diesel vehicles is to improve the low temperature activity of catalytic combustion of soot.LaCoO_(3)with different silver existence forms was synthesized by sol-gel and impregnation method,and the restriction mechanism of different Ag existence forms on catalytic combustion performance of soot was investigated.The results showed that the Ag on the surface of LaCoO_(3)was Ag_(2)O and Ag 0 when the calcination temperature was 250,450℃,respectively.Ag 0 and Ag+coexisted when the calcination temperature was 700℃.The catalyst synthesized by sol-gel and impregnation method at calcination temperature of 250℃showed the best catalytic performance,which was attributed to the interaction between Ag 2O and LaCoO_(3)support.