R dot approach for kinetic modelling of WGS over noble metals

Water Gas shift reaction (WGS) kinetics are prominent in reactions involving hydrocarbons. Often the rate expressions developed for WGS have narrow application for wider experimental conditions. On the other hand, DFT based microkinetic models developed for WGS can predict the experimental trend, however, developing rate expressions for the same can be difficult owing to the validity of different approximations and assumptions. In this context, R dot approach has been used in this study to develop rate expressions for WGS over Pt, Rh. Using this approach, the rate determining steps of the mechanisms proposed, validation with experimental data and most abundant reaction intermediate (MARI) analysis was carried out. Based on the interpreted results it has been seen that the R dot approach was able to predict the experimental trend to good degree of accuracy in line with the predictions of quasi steady state (QSS) approach.