H2O2 is a valuable, environmentally

H2O2 is a valuable, environmentally friendly oxidizing agentwith a wide range of uses from the provision of clean water to the synthesisof valuable chemicals. The on-site electrolytic production of H2O2 wouldbring the chemical to applications beyond its present reach. The successfulcommercialization of electrochemical H2O2 production requires cathodecatalysts with high activity, selectivity, and stability. In this Perspective, wehighlight our current understanding of the factors that control the cathodeperformance. We review the influence of catalyst material, electrolyte, andthe structure of the interface at the mesoscopic scale. We provide originaltheoretical data on the role of the geometry of the active site and its influenceon activity and selectivity. We have also conducted a series of originalexperiments on (i) the effect of pH on H2O2 production on glassy carbon,pure metals, and metal−mercury alloys, and (ii) the influence of cellgeometry and mass transport in liquid half-cells in comparison to membraneelectrode assemblies.