Solar oxidation of toluene over Co doped nano-catalyst
Cobalt (Co) co-doped TiO2 photo-catalysis were synthesized, characterized and tested toward solar
photocatalytic oxidation of toluene (TOL). A multi-technique approach was used to characterize and
relate the photo-catalytic property to photo-oxidation performance. Adding Co to TiO2 significantly
changed crystal size and surface morphology (surface area, pore-volume, and pore size), reduced the
bandgap energy of TiO2 and improved the solar photo-oxidation of TOL. Up to 96.5% of TOL conversion (%
TNconv) was achieved by using CoeTiO2 compared with 28.5% with naked TiO2. The maximum %TNconv
was achieved at high hydraulic retention time (HRT) 100 s, Co content in the photo-catalyst of 5 wt%
and relative humidity (%RH) of 50%. The mechanism of TOL solar oxidation was related to the concentration
of OH and O:
2 radicals produced from the generated electrons and holes on the surface of Co
eTiO2. The products formed during the photo-catalytic oxidation of TOL were mainly CO2 and water, and
minor concentration of benzene and benzaldehyde. Overall, the CoeTiO2 could be used as a potential
photo-catalyst for the oxidation of toluene in gas-phase streams on an industrial scale.