Photocatalytic reduction of CO2 to C1 Fuels by (Cu/ZnO)@TiO2 yolk-shell nanoreactors

• Main Authors: Li-ChunCheng, 鄭立群
• Other Authors: Hong-Paul Wang
• Format: Others
• Language: en_US
• Published: 2016
• Online Access: http://ndltd.ncl.edu.tw/handle/35886571628544269966

碩士 === 國立成功大學 === 環境工程學系 === 104 === The massive use of fossil fuels has resulted in excessive CO2 emission, which caused global warming and extreme climate change. Therefore, reduction of CO2 has become one of the most concerned issues worldwide. CO2 and H2O can be photocatalytically converted to C1-C2 chemicals or fuels for a natural carbon cycling. Therefore, the main objective was to study the feasibility for photocatalytic reduction of CO2 by the novel nanoreactors. The (Cu/ZnO)@C core-shell nanoparticles were synthesized by carbonization of Cu2+- and Zn2+-β-Cyclodextrin complexes at 673 K. In addition, TiO2 was coated on the surface of the Cu/ZnO nanocomposites to form (Cu/ZnO)@TiO2 core-shell nanoparticles. The core metals were partially etched to yield (Cu/ZnO)@C and (Cu/ZnO)@TiO2 yolk-shell nanoreactors for photocatalytic reduction of CO2. The core Cu/ZnO encapsulated in carbon-shell ((Cu/ZnO)@C yolk-shell) have average diameters of 3-18 nm. After a 6-h irradiation, CO2 in (Cu/ZnO)@C yolk-shell nanoreactors can be converted to methanol (8.31-9.38 μmol/g-ZnO). It seems that CuO plays the role of promoting photocatalytic activity and selectively for C1 products. The (Cu/ZnO)@C yolk-shell nanoreactors have greater methanol yields than the nano Cu/ZnO composites by 1.5-1.8 times mainly due to the fact of that the Arrhenius pre-exponential factors (A) between CO2 and photoactive sites within the nanoreactors are increased by 50-80%. However, after a 6-h irradiation, in the (Cu/ZnO)@TiO2 nanoreactors, 10.74-16.96 μmol/g-catalyst of C2H5OH are yielded. It is very likely that methanol and other C1 species in the (Cu/ZnO)@TiO2 yolk-shell nanoreactors may be polymerized with the photo-induced radicals, and converted to ethanol.