Effect of oxide interface on 60Co gamma radiolysis of water molecules was studied. Based on the molecular hydrogen yield when compared with that from the radiolysis of pure gas-phase water, all tested oxides can be classified into three groups: i) inhibitors - MnO2, Co3O4, CuO and Fe2O3; ii) oxides with H2 yields, which are similar to or slightly greater than radiolysis of pure gas-phase water - MgO, CaO, SrO, BaO, ZnO, CdO, Cu2O, NiO, Cr2O3, Al2O3, CeO2, SiO2, TiO2, Nb2O5 and WO3; iii) promoters - Ga2O3, Y2O3, La2O3, Nd2O3, Sm2O3, Eu2O3, Gd2O3, Yb2O3, Er2O3, HfO2, and ZrO2. H2O radiolysis enhancement for ZrO2 and other promoters is result of effective energy transfer at the oxide/water interface, presumably due to migration of excitons to the surface and their resonant coupling with the H2O adsorption complex. Plot "effective H2 yield vs. band-gap (Eg) energy" shows a maximum near 5 eV.
Revised: May 7, 2002 |
Published: July 15, 2001
Citation
Petrik N.G., A.B. Alexandrov, and A.I. Vall. 2001.Interfacial Energy Transfer during Gamma Radiolysis of Water on the Surface of ZrO2 and Some Other Oxides.Journal of Physical Chemistry B 105, no. 25:5935-5944.PNNL-SA-33910.