| Article ID | Journal | Published Year | Pages | File Type |
|---|---|---|---|---|
| 1332083 | Journal of Solid State Chemistry | 2011 | 8 Pages |
The visible photocatalytic mechanism of nitrogen-doped novel TiO2 was studied by means of electron spin resonance spectroscopy (ESR). It was found that, under visible light irradiation, the concentration of single-electron-trapped oxygen vacancy (SETOV, Vo•) of novel TiO2 remained unchanged, but that of nitrogen-doped novel TiO2 increased and returned to original state when the light was turned off. This implies that, aside from Vo• in bulk of nitrogen-doped novel TiO2, oxygen vacancy without trapped electron (Vo••) was formed on its surface. Vo•• as a surface electron trap captured photogenerated electron from the bulk to generate extra Vo•, carrying out photocatalytic reaction on the surface. At the same time, nitrogen doping product NO was chemically adsorbed on the vicinity of Vo•• and inhibited the attack of oxygen, allowing Vo•• to remain stable in air. The synergistic action of the two kinds of active structures, i.e., bulk Vo•–NO–Ti and surface Vo••–NO–Ti, accounted for the visible photocatalytic activity of N-doped novel TiO2.
Graphical abstractSynergistic action is realized between (Vo•)bulk and (Vo••)surf in the presence of active structures (Vo•)bulk–NO–Ti and (Vo••)surf –NO–Ti.Figure optionsDownload full-size imageDownload as PowerPoint slideResearch highlights► The origin of visible photocatalytic activity of the N-TiO2 was studied by ESR. ► (Vo•)bulk and (Vo••)surf formed in N-TiO2. ► (Vo•)bulk and (Vo••)surf show a synergistic effect in visible photocatalytic. ► TiO2 did not contain (Vo••)surf, so no visible photocatalytic activity.
