Al-Based Porphyrin Metal-Organic Framework for the Reduction of Carbon Dioxide to Formic Acid

In this study, a porphyrin-based photocatalyst, TCPP@AlMOF, was synthesized and thoroughly characterized for its ability to capture and convert CO₂ under xenon lamp illumination. The synthesized framework was confirmed through a combination of spectroscopic and structural analyses, including ¹H NMR, PXRD, BET, BJH, TGA-DSC, FTIR, and SEM. BET surface area measurements showed a decrease from 272.5 m²/g (before CO₂ reduction experiment) to 234.1 m²/g (after CO₂ reduction experiment), indicating effective interaction of CO₂ with the porous framework. The maximum CO₂ adsorption capacity was found to be 0.168 mmol/g, with a desorption efficiency of 4.44%, while regenerated TCPP@AlMOF retained partial adsorption capability, demonstrating its recyclability. FTIR and GC-MS studies confirmed the conversion of CO₂ into formic acid, with no significant byproducts detected. Electrochemical studies using LSV and chronoamperometry established the diffusion-controlled nature of the reduction process and the stability of the catalyst under operating conditions. Compared to other known photocatalytic systems, TCPP@AlMOF offers a visible light active, metal-free platform with efficient CO₂ reduction capability under mild conditions. This work highlights the potential of porphyrin-functionalized MOFs for sustainable CO₂ conversion.