Porphyrin-based metal-organic framework catalysts for photoreduction of CO: understanding the effect of node connectivity and linker metalation on activity

• Published in: New journal of chemistry Vol. 44; no. 36; pp. 15362 - 15368
• Main Author: Jin, Jiarui
• Format: Journal Article
• Language: English
• Published: 21.09.2020
• ISSN: 1144-0546; 1369-9261
• DOI: 10.1039/d0nj03507f

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 CO 2 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 CO 2 adsorption affinity. The CO 2 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 Zr 6 -oxo cluster connectivity and the introduced dual reaction sites when the porphyrin linkers were metalated with Zn( ii ) ions. The synergistic effect of linker defects and metalation on the photocatalytic activities of porphyrin-based MOFs.