Effects of Knudsen diffusivity on the effective reactivity of nanoporous catalyst media

•Non-equilibrium effects on the reactivity of nano-catalytic samples are investigated.•Non-equilibrium effects enhance the diffusivity of the medium.•The approach provides effective reactive lengths for catalytic devices. We investigate the non-equilibrium hydrodynamic effects on the reactivity of a nanoporous catalytic sample. Numerical simulations using the Lattice Boltzmann Method (LBM) show that non-equilibrium effects enhance the reactivity of the porous sample, in agreement with theoretical predictions [1]. In addition, we provide a quantitative assessment of the reactivity in terms of the thickness of the reactive layer inside the nanoporous catalytic sample. Such an assessment constitutes a first step towards integrated simulations encompassing nanoscale reactivity and transport coefficients within a macroscale description of experimental relevance.