We have studied the mechanochemical decomposition of TCP molecules confined between atomically-smooth iron, iron carbide, and iron oxide surfaces using NEMD simulations with ReaxFF. The iron surfaces are more effective in promoting TCP decomposition compared to iron carbide and particularly iron oxide surfaces, which correlates with the increase in Fe-C bonding between the molecules and the surface, as well as the surface energy. The decomposition of TCP initially proceeds through P-O bond dissociation for all of the surfaces to form cresol molecules.