Role of Manganese Oxide Nanosheets in Pyrolyzed Carbonaceous Supports for Water Oxidation

The oxygen-evolving complex in photosystem II, a manganese-oxide-based cluster, is nature’s solution for water oxidation, while most efficient artificial catalysts consist of costly noble-metal-based oxides. However, tackling the upcoming challenges of the climate crisis requires sustainable electrocatalysts based on affordable and efficient materials. Herein, we extensively probe carbonized iron phthalocyanine without and with deposited manganese-oxide nanosheets as model electrocatalysts mimicking the biological solution. We employed electrochemical and spectroscopic techniques, noise electrochemical scanning tunneling microscopy, and density functional theory calculations to understand their water-splitting performance holistically. Both compound materials show remarkable electrocatalytic activity, outperforming previously investigated systems based on earth-abundant elements. The origin of this enhanced performance is assigned to the metal centers and the edges at the substrate-nanosheet interface, providing the design guidelines to optimize further sustainable and affordable electrocatalysts for water oxidation.