Abstract
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•Cu-C/TiO2 nanoparticles were synthesized via sonicated sol-gel method.•Photocatalytic reduction of CO2 into CH3OH was successfully achieved using Cu-C/TiO2.•1gL−1 of 3wt%Cu-C/TiO2 exhibited maximum catalytic activity.•Methanol production by Cu-C/TiO2 was much higher than those of C/TiO2 and Degussa P25.
Photocatalytic reduction of carbon dioxide into methanol has been investigated by using Cu-loaded carbon modified titanium oxide (Cu-C/TiO2) nanoparticles under irradiation of UV and natural sunlight. Cu-C/TiO2 nanoparticles were prepared by sonicated sol–gel method. The synthesized photocatalyst exhibited maximum catalytic activity at the optimum dosage of 1.0gL−1 of Cu-C/TiO2 having 3wt% Cu content, giving maximum methanol yields of 2593 and 885μmolg−1 after 5h of illumination under UV and natural sunlight, respectively. The results indicated that the methanol yield produced by Cu-C/TiO2 was much higher than those of carbon modified titanium oxide (C/TiO2) and Degussa (P25-TiO2). This improvement was attributed to the reduced optical bandgap energy by C-modification, hindered electron-hole recombination by Cu-loading and the enhanced catalytic activity of Cu for the reduction of CO2 specifically to methanol.