High selective photocatalytic CO2 conversion into liquid solar fuel over a cobalt porphyrin-based metal–organic framework

In the present study, porphyrin-based metal–organic framework (Co/PMOF) was synthesized and characterized by different spectra analyses. The photoluminescence properties of porphyrin and Co/PMOF revealed that the photoluminescence of Co/PMOF was quenched compared to the porphyrin, indicating that the lifetime of photo-generated charge carriers in Co/PMOF is longer than porphyrin. The prepared Co/PMOF was applied as an efficient photocatalyst for CO2 photoconversion to formate in the presence of triethanolamine (TEOA) as a sacrificial agent under visible-light irradiation. The photoreaction results showed that 23.21 µmol HCOO− was produced over Co/PMOF during the 6 h photocatalytic reaction under visible illumination, showing much better activity than the porphyrin, 4.56 µmol HCOO−. No other products were detected, suggesting that this reaction over Co/PMOF has high selectivity. Co/PMOF reusability and stability were examined through recycling tests and there were no remarkable losses of photoactivity even after three cycles of photoreaction. Moreover, FTIR measurement and UV–Vis spectra demonstrated no notable changes in Co/PMOF structure. As a result, superior photocatalytic behavior of Co/PMOF was implied for CO2 photoreduction which highlights the great potential of assembly porphyrin and cobalt into MOFs for CO2 photoreduction.