Abstract
In this work we investigate a variety of chemical and photoinduced processes in which different hydrogenous species including molecules, ions, and atoms interact with the bulk of a complex nanoporous oxide . Our results provide a detailed and consistent explanation of the recently observed phenomenon of photoinduced conversion of the insulating H-doped to a conductor [K. Hayashi et al., Nature (London) 419, 462 (2002)]. The formation of a large and thermally stable concentration of electron centers in this process is facilitated by a large concentration (up to ) of extraframework naturally present in this material and homogeneously distributed in its bulk. We show that these species are able to split molecules into pairs of and ions and convert atoms into and promoting the photoinduced conversion process. The similarity of the mechanisms described in this work to those known for low-coordinated sites at MgO surfaces indicates that the formation of electronic centers in oxides interacting with hydrogenous species could be a generic feature.
2 More- Received 3 June 2005
DOI:https://doi.org/10.1103/PhysRevB.73.045120
©2006 American Physical Society