Supreetha J
For detailed information, kindly refer to "Enabling Reactions in a Porous Zone" section uder Porous Media Conditions in the Ansys User's Guide
If you are not able to access the link, please refer to this forum discussion:
To incorporate the Arrhenius equation constants into the porous media model, you can define a reaction rate expression using UDF and use this in the wall surface reaction model.
I hope this helps.