We have developed a new solver for OpenFOAM®, that allows for the solution of Navier-Stokes equations for complex and general geometries for reacting flows at surfaces, based on microkinetic descriptions of the surface reactivity. The CatalyticFOAM solver exploits state-of-the-art and new numerical technique in order to enable the simulation of multidimensional systems with complex kinetic mechanisms. CatalyticFOAM is an valuable tool for the first-principles based multiscale analysis of catalytic processes and paves the way towards the rational understanding and development of new reaction/reactor concepts.