Electrocatalytic water oxidation over AlFe(2)B(2)

We report excellent electrocatalytic performance by AlFe(2)B(2) 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(–2) 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(2)B(2) and the formation of Fe(3)O(4) nanoclusters on the exposed [Fe(2)B(2)] layers. Thus, the AlFe(2)B(2) structure serves as a robust supporting material and, more importantly, as a pre-catalyst to the in situ formed active electrocatalytic sites. Comparative electrochemical measurements demonstrate that the electrocatalytic performance of the AlFe(2)B(2)-supported Fe(3)O(4) nanoclusters substantially exceeds the results obtained with unsupported nanoparticles of Fe(3)O(4), FeB, or such benchmark OER catalysts as IrO(2) or RuO(2). The excellent catalytic performance and long-term stability of this system suggests that AlFe(2)B(2) can serve as a promising and inexpensive OER electrocatalyst.