CO- and NO-Induced Disintegration and Redispersion of Three-Way Catalysts Rhodium, Palladium, and Platinum: An ab Initio Thermodynamics Study

Disintegration of supported nanoparticles (NPs) in the presence of reactants can lead to catalyst deactivation or be exploited to redisperse sintered catalysts. To better understand the stability of TiO 2 (110)-supported three-way catalysts Rh, Pd, and Pt NPs during NO x and CO reduction, we present an ab initio thermodynamics study of the feasibility for these NPs to disintegrate into adatom-reactant complexes across a large parameter space of temperatures, pressures, and sizes. The tendencies for disintegration and redispersion between supported Rh, Pd, and Pt NPs are established. Compared to both Pd and Pt, Rh NPs are found to be more susceptible to either NO- or CO-induced disintegration, due to the large and exothermic formation energy of the Rh adatom complexes. Moreover, NO is a more efficient reactant for particle redispersion than CO. These findings provide valuable insights for how to either prevent reactant-induced NP disintegration or facilitate reactant-induced redispersion of sintered catalysts.