It is very much challenging to rationalize the designs of nanostructured heterogeneous catalysts because the effects of geometry and interface properties are negelected in the conventional computation-aided catalyst design principles. In this presentation, I will introduce how simple ab initio calculations can be used for 3D/2D heteregeneous electrocatalysts, whose interface atomic configurations can be controlled based on ab initio-thermodynamics calculations. Using the theoretically obtained interface dipole moments parameter for various N-doping structures of graphene encapsulating metal oxide particle, we performed finite element method (FEM) simulations to quantitatively study the effects of interface on the ion transport and current density during oxygen evolution reaction (OER). We found that depending on the interface atomic configurations, the current density can be largely changed by upto 5 factors for metal oxide nanoparticle having diameter of 5-10 nm. These predictions of our theory and modeling were demonstrated with our experiments. This work make an advancement in the designs of catalysts, especially when the ion transport is the limiting factor of the overall activities.