摘要
理论分析和实验结果表明催化过程中催化剂不参加化学反应,催化剂本身不发生化学变化,化学反应模式催化循环反应不可能发生,1902年提出的化学反应模式的催化循环原理(Sabatier's principle and Boudar'ts prin-ciple)难以令人信服。简述了触媒理论的逻辑推理及实验验证。触媒理论认为催化循环是催化剂质点内运动的电子轨道变形与恢复的循环,催化剂(或促进剂)有助于变形了的轨道恢复,而毒化剂则使变形了的轨道进一步变形;认为载体材料对贵金属催化剂催化活性的影响犹如催化剂(或促进剂)或毒化剂。凡是电负性大于贵金属催化剂的酸性材料作为载体都会降低金属催化剂催化活性,为了达到相同的转化率,必须要用较多的贵金属催化剂。Cl、O、N、C、S、P、SiO2、Al2O3、B2O3、硅藻土以及菫菁石陶瓷等都是酸性元素或材料。凡是电负性小于贵金属的碱性材料和过渡族元素都能提高贵金属的催化活性,如果达到同样的排放标准,则可以节省许多贵金属。汽车尾气净化催化剂用的Fe-Cr-Al金属卷片蜂窝载体优于陶瓷蜂窝载体。粉末冶金多孔金属蜂窝载体的最大优点是涂层量多而又不易剥落,起燃温度低,远优于金属卷片蜂窝载体。
Both theoretic tion and itst chemical states are analysis and experimental results show unchangeable. During the past century that catalysts don＇t take part in chemical reac- the Sabatier＇s principle and Boudart＇s principle which propose catalysts join the chemical reaction are unable to account for many catalysis processes such as the alkali metal carbonates, alkaline metal carbonates, transition metal and noble metal catalysis procesS. The ECDAT＇s （elec- tron cyclic donate-accept catalysis theory--ECDAT or catalysis theory） logical reasoning and it＇s experimental verifica- tion is described . The ECDAT consider that the catalytic cycle is a cycle between the deformation and returning of e- lectron orbits of noble metal catalysts happened in catalytic cycle reaction. The promoter is helpful to returning of elec- tron orbit of noble metal catalyst. The poison make the further deformation of deformed electron orbit of noble metal. The relative catalytic activity of promoter depends on their electro-negativity value relative to the noble metal. The value of electro-negativity of promoter is less than that of noble metal and the value of electro-negativity of poison is more than that of noble metal. The support behaves as promoter or poison. The acidic materials such as Ala Oa, active car- bon and cordierite are a poisons to noble metal catalyst . The transition metal is a promoter to noble metal catalyst. Fe-Cr-A1 metal film honeycomb as support is better than that of ceramic honeycomb. P/M porous metal honeycomb is better than film honeycomb. For example, when the amount of noble metal being loaded on P/M porous metal honey- comb is only one half of that on ceramic support, It＇s light-off temperature （Ta0） dropped by 100- 150℃.
出处
《材料导报》
EI
CAS
CSCD
北大核心
2012年第5期52-61,共10页
Materials Reports
关键词
载体
复相催化
贵金属催化剂
ECDAT
support, heterogeneous catalysis, noble-metal catalyst, ECDAT
