This review volume highlights advances in both theoretical and experimental techniques and points out both the progress made and the challenges to overcome in the near future. The topics cover a broad spectrum going from surface characterization, investigation of thermodynamics and kinetics mechanistic pathways, electrochemical experiments and theory, multi-scale modeling applied to synthesis and growth processes such as electrodeposition, and corrosion reactions arising from the nanosize of electrocatalysts that affect their lifetime and activity.