Methane formation over TiO2-based photocatalysts: Reaction pathways

- Methane formation was observed after irradiation if TiO2 in the CO2 free atmosphere.
- Methane was not formed from 13CO2 present in gas mixture.
- CH4 was formed from the carbon compounds incorporated into TiO2 photocatalysts.
- CH4 formation and oxidation over TiO2 photocatalysts occurs at the same time.