Mimic the Photosystem II for Water Oxidation in Neutral Solution: A Case of Co3O4.

Abstract: The photosystem II (PSII) in green plants exhibits marvelous oxygen production in neutral environments. However, artificially developed oxygen evolution catalysts (OECs) show much less activity, and the oxygen evolution reaction (OER) is now becoming a bottleneck in many energy‐related issues. Here, the PSII is mimicked to design an efficient OER system in neutral environments by introducing an oleylamine (OAm) organic layer to cap the Co3O4 OEC, and employing buffers as proton shuttles in the system. Consequently, the activity is largely enhanced. The current density can reach 10 mA cm−2 at an overpotential (η) of 390 mV in the best case in neutral environment. The turnover frequency is 0.0117 at η of 400 mV, almost the same as that in 1 m KOH solutions. The surface chemistry of the Co3O4 OEC indicates that the OAm can promote the activity. The reason that buffers as proton shuttles can greatly facilitate the reaction is ascribed to the proton‐coupled electron transfer process in the OER mechanism. These results may stimulate new perspectives on mimicking natural systems as well as new insights in electrocatalysis. [ABSTRACT FROM AUTHOR]