Room temperature water splitting at the surface of magnetite

G.S. Parkinson, Z. Novotný, P. Jacobson, M. Schmid, U. Diebold

Institut für Angewandte Physik, Technische Universität Wien, 1040 Wien, Austria

J. Am. Chem. Soc. 133 (2011) 12650-12655

An array of surface science measurements has revealed novel water adsorption behavior at the Fe3O4(001) surface. Following room temperature exposure to water, a low coverage of hydrogen atoms is observed, with no associated water hydroxyl group. Mild annealing of the hydrogenated surface leads to desorption of water via abstraction of surface oxygen atoms, leading to a reduction of the surface. These results point to an irreversible splitting of the water molecule. The observed phenomena are discussed in the context of recent DFT calculations [Mulakaluri, N.; Pentcheva, R.; Scheffler, M. J. Phys. Chem. C 13 2010, 114, 11148], which show that the Jahn-Teller distorted surface isolates adsorbed H in a geometry that could kinetically hinder recombinative desorption. In contrast, the adsorption geometry facilitates interaction between water hydroxyl species, which are concluded to leave the surface following a reactive desorption process, possibly via the creation of O2.

Corresponding author: G. S. Parkinson (parkinson at iap_tuwien_ac_at).

Users with online access to the Journal of the American Chemical Society can load the article from the publisher.