Paramagnetic species in nitrogen-doped ZnO (N-ZnO) powders, visible light sensitive photocatalysts exhibiting antibacterial activity, have been investigated using EPR spectroscopy. The N-ZnO photocatalysts showed two kinds of EPR signals due to a singly ionized nitrogen (N2-) and a shallow donor. Visible light irradiation to the N-ZnO particles shows reversible response of reduction of EPR signal of the N2- radical site and increase of that due to shallow donor. The results indicate that the N2- is converted to a diamagnetic neutral molecular nitrogen acceptor (N20) by visible light and photoinduced electrons are trapped to the shallow donor sites.
ASJC Scopus subject areas
- Physics and Astronomy(all)
- Physical and Theoretical Chemistry