Recent progresses in predictive modeling methods together with high-fidelity experimental characterization techniques that take device operation condition into consideration led to significant advancements in understanding how microscopic interfacial processes propagate to macroscopic device behavior. In this talk, we will overview our computational modeling efforts within HydroGEN consortium based on various method such as ab-initio atomistic modeling and continuum model, wherein the state-of-art characterization techniques are fully leveraged for the reliability of our interpretation. As examples, we will present our recent activities to improve understanding about the mechanisms that dictate performance and durability of hydrogen production devices, where considering operating conditions and integration with experimental characterization often played critical roles [1-6]. More specifically, we will discuss how computational models have helped to elucidate mechanisms of interface chemistry, formation of new phases, and the impact of interfaces on key reaction pathways that are intimately related to the device performance and durability, wherein experimental characterization data was used as the constraint for our models and obtain new understanding of interfacial phenomena relevant for the performance of hydrogen production techniques. Finally, we will discuss how the obtained knowledge can be used to develop strategies for improving materials used in hydrogen production technologies. This work was supported by the U.S. Department of Energy, Energy Efficiencies and Renewable Energies Office, Hydrogen and Fuel Cells Technologies Office, and was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under contract DE-AC52-07NA27344.