Porosity in nanoparticles and their ensembles can profoundly alter a system's electrochemical behaviour by both changing the number and identity of the available catalytic sites, and through influencing the mass transport in the vicinity of the electrochemical interface. This review focuses first on recent advancements in characterising porosity and heterogeneity at the nanoscale and second on developments in electrochemical simulation which provide insight into how a porous architecture can lead to apparent ‘catalytic’ effects by virtue of altering the masstransport in the vicinity of the electrode
