Porphyrin-based metal–organic framework catalysts for photoreduction of CO2: understanding the effect of node connectivity and linker metalation on activity. (8th September 2020) - Jin, Jiarui
Abstract : The synergistic effect of linker defects and metalation on the photocatalytic activities of porphyrin-based MOFs. Abstract : Three zirconium–porphyrin based MOFs with different linker connectivity, PCN-222, PCN-223 and PCN-224, and their Zn(ii ) ion metalated analogues, were prepared and used as catalysts for the photoreduction of CO2 under visible-light irradiation. Before metalation with Zn 2+ in the porphyrin linkers, the lowest linker-connected PCN-224 (6-fold) exhibited a higher formate yield rate of 45.2 μmol g −1 h −1 compared to PCN-222 and PCN-223. However, after the incorporation of Zn 2+ into the porphyrin, PCN-222-Zn showed the highest formate yield rate of 120.2 μmol g −1 h −1 . The density functional theory (DFT) computational results revealed that the catalytic activity correlated with the CO2 adsorption affinity. The CO2 adsorption energy on PCN-222-Zn (294.4 kJ mol −1 ) was the highest among all of the samples. The overall catalytic performance was affected by the Zr6 -oxo cluster connectivity and the introduced dual reaction sites when the porphyrin linkers were metalated with Zn(ii ) ions.