In this study, we use NEMD simulations with ReaxFF to compare the mechanochemical decomposition of TCP molecules confined between different ferrous surfaces over a range of temperatures and pressures. We observe significant differences in the mechanochemical reactivity of TCP on iron, iron oxide, and iron carbide surfaces. The variations in reactivity can be explained by differences in surface energy and stiffness, which can be ac- Systems shown after minimisation and equilibration, but before heating, compression, and shear. Rendered using OVITO. counted for in theoretical models for mechanochemistry.