The composite photocatalyst comprising p-type NiO and n-type TiO 2 showed improved photoactivity due to the inhibition of electron-hole recombination. A series of P-N junction photocatalysts, NiO/TiO2, were prepared by incipient wetness impregnation. The photocatalysts were characterized by UV-vis spectroscopy, XRD and XPS. The photoactivity of photocatalysts was tested by the degradation of methylene blue. The results showed that 0.5 wt.% NiO/TiO2 had the highest activity as compared with TiO2. A P-N junction mechanism was proposed and verified that the photocurrent could be enhanced under forward bias in the NiO/TiO2 film. The photoactivity enhancement is attributed to P-N junction and co-catalyst effects.
Bibliographical noteFunding Information:
The authors would like to acknowledge the National Science Council of Taiwan for financial support of this research under contracts NSC 99-2923-E-002-002-MY2 and NSC 99-2120-M-002-012 .
- P-N junction