Eco-Friendly Photocatalytic Transformation of Greenhouse Gas CO2 into Precious CH4 Fuel via Cu-Deposited Black TiO2 under Simulated Sunlight Irradiation

초록

Hereunder, the eco-friendly photocatalytic CO2 transformation capability of Cu-deposited black TiO2 (Cu/BTiO2) was evaluated to investigate if this photocatalyst proceeds the thermodynamically- and kinetically-satisfactory CO2 transformation into CH4. The clustered Cu-deposited BTiO2 (Cu/BTiO2) and Cu/BTiO2 architectures revealed noticeable photocatalytic CO2 transformation abilities, whereas the pristine TiO2 and BTiO2 catalysts displayed no significant photocatalytic CO2 transformation abilities. Especially, the photocatalytic CO2 transformation rates of a representative Cu/BTiO2 architecture were 104, 209, 272, 322, and 361 μmol/g at the irradiation times of 2, 4, 6, 8, and 10 h, respectively, while the photocatalytic CO2 transformation rates of Cu/BTiO2 were 61, 139, 217, 270, and 309 μmol/g at the same irradiation times, respectively. The promoted photocatalytic CO2 transformation ability of the Cu/BTiO2 architecture was assigned to the excellent electron‒hole separation tendency, which was verified by the photoluminescence analysis. The composition ratio of Cu incorporated into BTiO2 in the Cu/BTiO2 architectures was crucial in CH4 generation. In addition, the Cu/BTiO2 architecture displayed eminent photodurability, which was verified by the consecutive experiment cycle, and the mechanistic process for CO2 transformation into CH4 via the Cu/BTiO2 architecture was established. The electronic framework of the Cu/BTiO2 architecture was established on the basis of its band gap and valence band value. Conclusively, the Cu/BTiO2 architecture is an outstanding tool for thermodynamicallyand kinetically-satisfactory photocatalytic CO2 transformation into CH4 that application under simulated sunlight irradiation.

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