A multiscale modeling framework is described and applied to the reactivity of iron oxide nanoparticles in a chemical looping reforming (CLR) reactor. At the atomic scale/nanoscale, we have performed kinetic Monte Carlo modeling, guided by Density Functional Theory calculations, on the detailed kinetics of the CH4 conversion to products as a function of temperature. These results have been post-processed for use in macroscopic models with the goal to integrate process information with materials information. Two levels of macroscopic models have been used to evaluate the performance of the nanoparticles in their final application: (1) a pore-unresolved infra-particle transport model that accounts for limitations via an effective diffusivity and an effectiveness factor, and (2) a fluid-particle multiphase flow model that allows the study of the consequences of clustering and infra-particle transport on overall reactor performance. This modeling approach ultimately leads to better descriptors of material performance that can be used in future materials screening activities.