Effective visible-light CO2 photoreduction over (metallo)porphyrin-based metal-organic frameworks to achieve useful hydrocarbons

Metal-organic frameworks (MOFs) have proved to be particularly appropriate for CO2 conversion. In the present work, we report metalloporphyrin-based MOFs, PCN-222(M) (M = Fe, Co, Ni, and Cu), which promote photocatalytic CO2 conversion to valuable chemicals. These ultra-highly stable frameworks are constructed from Zr-6 clusters and metalloporphyrin linkers. Metalloporphyrinic MOF has been synthesized and employed as a visible-light photocatalyst for carbon dioxide to form formate. The effect of metalloporphyrinic PCN-222(M) on CO2 reduction has been studied. Remarkably, PCN-222(M) is highly efficient in visible light-driven CO2 reduction into formate ion compared with the nonmetal porphyrinic PCN-222. Metal ions of porphyrinic linkers play a great role in CO2 sorption, light harvesting, bandgap, photoluminescence (pL) intensity, and charge transfer, which influence CO2 reduction. CO2 adsorption and activation over metal ions of porphyrinic linkers play a significant part in the improvement of the conversion efficiency; the product obtained was characterized by gas chromatography/mass spectrometry (GC/MS) and ion mobility spectrometry (IMS) analyses. The reaction mechanism has been discussed in detail.

Automated summary

Metalloporphyrin-based MOFs, PCN-222(M), have been shown to be efficient photocatalysts for converting CO2 into valuable chemicals. The metalloporphyrinic MOFs exhibit high stability and enhanced CO2 reduction compared to nonmetal porphyrinic MOFs.