Elucidating the Active Sites and Synergies in Water Splitting on Manganese Oxide Nanosheets on Graphite Support

Photosystem II is nature's solution for driving the oxygen evolution reaction to oxidize water. A manganese-oxide cluster is this protein's active center for water splitting, while the most efficient man-made catalysts are costly noble metal-based oxides. Facing the climate change, research on affordable and abundant electrocatalysts is crucial. To mimic the biological solution, manganese oxide nanosheets are synthesized and deposited on highly-oriented pyrolytic graphite. This electrocatalyst is then examined with spectroscopic and electrochemical measurements, electrochemical noise scanning tunneling microscopy, and density functional theory calculations. The detailed investigation assigns the origin of its enhanced water-splitting performance to detected activity at the nanosheet edges which the proposed mechanism explains further. Therefore, the results provide a blueprint for how to design efficient electrocatalysts for water oxidation with abundant materials.