Exploring electronic structure and photophysical properties of metalloporphyrin-based metal–organic frameworks for photocatalysis: A quantum chemistry study

Hydrogen production is gaining interest as a clean energy source, with photocatalytic water-splitting being a key method due to its eco-friendly nature. Metalloporphyrins-based MOFs (TCPP(M)-MOFs), due to their tunable optical properties, are excellent materials for hydrogen evolution via water-splitting using sunlight. In this research, TCPP(M)-MOFs containing nodes based on metal ion d10 Zn2+ and TCPP(M) as linkers (M = Fe2+, Ni2+, Co2+and Cu2+) has been studied using theoretical approach. The electronic structure and optical properties of all Zn-TCPP(M)-MOFs were investigated using the density functional theory (DFT) and periodic-DFT calculations. The study revealed a bandgap reduction related to the open-shell metals in the TCPP linker, with an optimal value for the photocatalytic process under sunlight. TD-DFT calculations show that the inclusion of open shell ions enhances the linker-centered ligand-to-metal charge transfer process. Finally, it was suggested some directions for the design of new melloporphyrine-based MOFs, potentially leading to new materials for photocatalytic water-splitting.