In catalytic cracking processes due to the severe temperature conditions there also is thermal cracking reactions. Regarding naphtha cracking on ZSM-5, do you think ethylene is a thermal or a catalytic product?
This greatly depends on the temperature, amount of catalyst and reactor configuration, but of course it should be mostly catalytic reaction product. The other factor is the selectivity of the catalyst. Its very easy to check, just run the reaction with same conditions but without the catalyst.