Electrocatalytic water oxidation over AlFe 2 B 2

We report excellent electrocatalytic performance by AlFe B in the oxygen-evolution reaction (OER). The inexpensive catalytic material, prepared simply by arc-melting followed by ball-milling, exhibits high stability and sustained catalytic performance under alkaline conditions. The overpotential value of 0.24 V observed at the current density of 10 mA cm remained constant for at least 10 days. Electron microscopy and electron energy loss spectroscopy performed on the initial ball-milled material and on the material activated under electrocatalytic conditions suggest that the catalytic mechanism involves partial leaching of Al from the layered structure of AlFe B and the formation of Fe O nanoclusters on the exposed [Fe B ] layers. Thus, the AlFe B structure serves as a robust supporting material and, more importantly, as a pre-catalyst to the formed active electrocatalytic sites. Comparative electrochemical measurements demonstrate that the electrocatalytic performance of the AlFe B -supported Fe O nanoclusters substantially exceeds the results obtained with unsupported nanoparticles of Fe O , FeB, or such benchmark OER catalysts as IrO or RuO . The excellent catalytic performance and long-term stability of this system suggests that AlFe B can serve as a promising and inexpensive OER electrocatalyst.