Photocatalytic CO ₂ Reduction on Phthalocyanine Platform

Inspired by natural photosynthesis, researchers are currently focused on light as a renewable energy source for designing Z-schemes for CO₂ valorization. Porphyrin present in the chlorophyll plays a crucial role in natural light harvesting during photosynthesis for CO₂ fixation. An analogue of porphyrin, Metallo phthalocyanine was utilized to fabricate a Z-scheme for CO₂ reduction. Metallo phthalocyanines acted as a promising photocatalyst and an efficient photosensitizer owing to their absorption in the NIR-I region, ability to generate ROS upon light illumination, and easy property modulation by changing the central metal atom or peripheral/nonperipheral substitution with electron donor or acceptor groups. In the research of CO₂ valorization, an application of phthalocyanines as a photocatalyst or a photosensitizer to create a heterojunction integrating with a suitable semiconductor is continuously rising. Primarily, phthalocyanine-based heterojunctions were designed based on metal oxides, C₃N₄, GO semiconductors or COFs typically suitable for CO₂ to CO transformation. However, a fewer approach for CO₂ reduction to make a variety of value-added products such as CH₄, CH₃OH, HCOOH, C₂H₅OH, and CH₃COOH was also reported. In this article, the role of phthalocyanine, both as a photocatalyst and a photosensitizer, in the designing of an efficient Z-scheme for CO₂ valorization were critically reviewed.