Production of Methanol as a Fuel Energy from CO 2 Present in Polluted Seawater - A Photocatalytic Outlook

The production of methanol by photocatalytic reduction of the CO 2 present in the different polluted seawater systems was explored using P–25, C/TiO 2 , and Cu-C/TiO 2 under both UV and sunlight. Both C/TiO 2 and Cu-C/TiO 2 were synthesized by the sonicated sol-gel method. The prepared photocatalyst demonstrated maximum efficiency when the dosage of photocatalysts was 1g/L and the doping level was 3wt% of copper. The maximum methanol yields of two observed polluted seawater systems were 2910 μmol/g and 2250 μmol/g after 5 hour illumination of UV light. However, the 5 hour natural sunlight illumination generated the yield of 990 μmol/g and 910 μmol/g of methanol. The observed results demonstrated that band gap narrowing of the photocatalyst by carbon modification and the restriction of electron-hole pair combination by copper doping both greatly enhanced the photocatalytic reduction of CO 2 to methanol under both UV and natural sunlight.