Layer by layer assembly of a bio-inspired manganese cluster for electrocatalytic water oxidation

Mn12O12(O2CC6H3(NH2)2)16(H2O)4 (Mn12DA) is a structural mimic of the oxygen-evolving-complex in photosystem II. Herein we describe a method to integrate the Mn12DA with ITO electrodes using a layer-by-layer approach. Using (3-Aminopropyl)triethoxysilane, (APTES), glutaraldehyde, Mn12DA, and sodium cyanoborohydride as a mild reducing agent, five layers of the electrocatalysts with maximal electrocatalytic currents were obtained. The integration method limits the ligand self-oxidation and prevents the catalyst failure. Furthermore, the developed configuration enables efficient water oxidation electrocatalytic reaction at pH = 7, with an overpotential of 430 mV, a faradaic efficiency of 92% and a high turn-over-number.