Tentative explanation for the kinetic compensation effect in doped catalysts

被引:5
作者
Marban, Gregorio [1 ]
del Rio, Laura [1 ]
机构
[1] CSIC, Inst Nacl Carbon INCAR, Oviedo 33011, Spain
关键词
compensation effect; reaction rate; activation energy; heterogeneous catalysis; DECOMPOSITION; PARAMETERS;
D O I
10.1134/S0023158413040149
中图分类号
O64 [物理化学(理论化学)、化学物理学];
学科分类号
070304 ; 081704 ;
摘要
The kinetic parameter compensation effect displayed by heterogeneous catalysts may occur when the global reaction is a combination of competing reactions which show the same mechanism and take place on different groups of active centres, each group showing different activation energy and pre-exponential factor values. In this study, a simple procedure is described for employing apparent kinetic data (lnA and E (a)) that show a compensation effect in order to calculate the activation energies and pre-exponential factors (proportional to the population densities) of active centres that present equal reaction mechanisms in dual site catalysts. The procedure was used to reproduce apparent kinetic data taken from the literature and obtained from experiments with doped-catalysts prone to dual-site catalytic behaviour. The fittings obtained in all cases were very good. The population density of active centres with activation energy showed constant growth with the increase in doping agent content, whereas that of the active centres originally present in the undoped catalysts showed varying trends.
引用
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页码:463 / 468
页数:6
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