Photocatalytic Chemical CO2 Fixation by Cu-BDC Nanosheet@Macroporous–Mesoporous-TiO2 under Mild Conditions

Growing greenhouse gas CO2 is driving the research on the chemical fixation of CO2. Here, the organic reaction of CO2 with benzyl halogen for chemical CO2 fixation under ambient conditions with irradiation of ultraviolet light is successfully catalyzed by Cu-BDC nanosheet@macroporous–mesoporous-TiO2 (Cu-BDC@macro–meso-TiO2), which shows high photocatalytic activity for both benzyl chloride and bromide reacting with CO2. Meanwhile, the prepared Cu-BDC@macro–meso-TiO2 possesses a three-scale porous structure, including macropores, mesopores, and micropores. In the uniform hierarchical structure, the microporous Cu-BDC nanosheet is confined in the macropore of macroporous–mesoporous-TiO2, while the ordered mesoporous structure is in the macroporous walls. This multilevel porous distribution can significantly improve the active surface areas and mass transfer efficiency of Cu-BDC@macro–meso-TiO2. Therefore, this finding has opened a field of research on photocatalytic chemical CO2 fixation.