A practically useful catalyst for removing nitrate and NDMA from drinking water must satisfy a number of criteria, from high activity and selectivity to desired products, to robustness against interference and

poisoning, to low cost and high durability. The ability to rationally design-in these characteristics can be greatly enhanced by reliable molecular-level models of catalyst function. In this work, we use density functional theory (DFT) simulations and supercell models to examine key molecular steps in the catalytic hydrogenation of NDMA at Ni and Pd metal surfaces. We examine the principle fragmentation products and contrast the thermodynamics and kinetics of dissociation steps. The

implications for both catalyst activity and selectivity are discussed.