Photo reduction of CO2 to methanol via TiO2 photocatalyst
Journal
International Journal of Photoenergy
Journal Volume
7
Journal Issue
3
Pages
115-119
Date Issued
2005
Author(s)
Abstract
Greenhouse gas such as CO 2 is the primary cause of global warming. Alternative energy source should be provided without producing more CO 2 , such as solar energy. One of the best routes to remedy CO 2 is to transform it to hydrocarbons using photo reduction. In our study, CO 2 was photocatalytically reduced to produce methanol using a Hg lamp with wavelength 365 nm in a steady‐state optical‐fiber photo reactor. The optical‐fiber photo reactor, comprised of near 120 Cu/TiO 2 ‐coated fibers, was designed and assembled to transmit and spread light uniformly inside reactor. TiO 2 film was coated on optical fiber using dip‐coating method. Titania and Cu‐loaded solutions were prepared by a thermal hydrolysis method. The thickness of Cu/TiO 2 film was 53 nm and consisted of very fine spherical particle with diameter of near 14 nm. The XRD spectra indicated the anatase phase of all TiO 2 and Cu/TiO 2 films. The wavelength of absorption edge was on 367 nm, equivalent to near 3.3 eV. Most active Cu species on TiO 2 surface were Cu 2 O clusters, and played an important role for the formation of methanol. The methanol yield increased with UV irradiative intensity. Photo activity increased with increasing Cu loadings. Maximum methanol rate was 0.45 μ mole/g‐cat•hr using 1.2 wt%‐Cu/TiO 2 catalyst under 16 W / cm 2 irradiation, 1.3 bar pressure of CO 2 , and 5000 seconds mean residence time. Higher than 1.2 wt% Cu loading gave less rate of methanol yield because of the masking effect of Cu 2 O clusters on the surface of TiO2.
SDGs
Type
journal article