Reaction mechanism of H2 generation for H2O/Zn/Fe3O4 system

Several ideas on the reaction mechanism of H2O/Zn/Fe3O4 water splitting system were considered from the aspect of Zn mobility. The vapor deposition of Zn onto the Fe3O4 surface was confirmed by H-2 generation reaction with Zn and Fe3O4 set separately. XPS measurements suggested that the surface of Fe3O4 is covered by Zn before the reaction with steam. The rapid reaction process has been supported by this Zn deposition, which greatly enlarges the number of sites of Zn/Fe3O4 pair that is ready to react with steam. In order to keep the Zn from vaporizing off the system, the Zn/Fe3O4 mixture was covered with additional Fe3O4 to capture the Zn vapor. This resulted in improved H2 yield of 99.5%. (C) 2002 Published by Elsevier Science Ltd on behalf of the International Association for Hydrogen Energy.