Mechano-catalytic water-splitting

The simultaneous H-2 and O-2 evolutions can be achieved by just stirring a powder of a p-type semiconductor, such as Cu2O, NiO, Co3O4 or Fe3O4 in dist illed water at room temperature. Frictional rubbing of the stirring rod ont o the bottom of the glass vessel is an important condition. The friction be tween the stirring rod and the glass surface generates an electrostatic fie ld to make a field emission of positive holes from the semiconductor-powder . which is fixed in the micro crack spaces on the glass surface. The emitte d positive holes react with water molecules to evolve O-2 and protons, whic h go to the glass surface and combine with the electrons there to evolve H- 2. The energy conversion mechanism, the generation of frictional electricit y, the effect of the water, the carrier-tunnelling emission probability, th e hopping conduction in the semiconductor, and the effects of fluid dynamic s, are discussed. (C) 2000 Elsevier Science Ltd. All rights reserved.