Insights on Oxygen Reduction Reaction to H2O2: The role of functional groups and textural properties on the activity and selectivity of doped carbon electrocatalysts

Abstract

Hydrogen peroxide (H2O2) is a key molecule in chemical industrial processes and alterative processes and catalysts are needed to achieve a green in-situ generation. The electrochemical two-electron oxygen reduction (2e-ORR) reactions are one of the most attractive routes along with the water oxidation or the direct synthesis. Here, we focused on the 2e-ORR, summarizing the recent advances in the finalization of catalysts for specifically catalyse the generation of H2O2 and technical measures to improve material screening, especially to obtain reliable activity and selectivity data. Firstly, a brief overview of metal-free catalysts is given and secondly a focus on how different strategies are adopted to improve activity and selectivity is reported. Such strategies include to tune the thermodynamic energy barriers by changing the material composition/functionalization and/or to facilitate mass transfer for reactants and products by acting on morphology. Finally, a brief overview of challenges in ink and electrode preparation for the correct screening of H2O2 electrocatalysts is reported.