Mechano-catalysis—a novel method for overall water splitting

Abstract

A novel finding of mechano-catalytic overall water splitting by metal oxides, a way to produce hydrogen by water decomposition, is reported. It was clearly revealed that some simple and mixed oxide powders such as NiO, Co3O4, Cu2O, Fe3O4, and CuMO2 (M=Al, Fe, Ga), when suspended in distilled water by magnetic stirring, decompose water into H2 and O2 catalytically. The observed mechano-catalytic overall water splitting was cycled by the conversion of mechanical energy supplied by rubbing these oxide powders against the bottom wall of the reaction vessel with the stirring rod. Typical efficiency of the mechanical-to-chemical energy conversion was estimated to be 4.3% (for NiO).