Ethylenediamine-functionalized CdS/tetra(4-carboxyphenyl)porphyrin iron (III) chloride hybrid system for enhanced CO2 photoreduction

The hybrid coupling between inorganic semiconductor and molecular catalyst can provide a promising approach for the construction of highly efficient and selective photocatalytic CO2 reduction systems. This hybrid system can take full advantage of the strong light harvesting capability of semiconductor and high selectivity of molecular catalyst. The interaction linker bridging the semiconductor and molecular catalyst plays an important role in supplying efficient electron transfer channels. In this study, both CdS with and without ethylenediamine functionalization (i.e., CdS-EF and CdS) have been successfully synthesized and further respectively coupled with tetra(4-carboxyphenyl)porphyrin iron(III) chloride (FeTCPP) for CO2 photoreduction. It is found that CdS-EF exhibits inferior photocatalytic activity to CdS, while CdS-EF/FeTCPP hybrid photocatalyst shows much higher activity than CdS/FeTCPP. This is because hydrogen bonding exists between the amino groups in CdS-EF and carboxyl groups in FeTCPP, which can act as electron transfer channels from CdS to FeTCPP in the obtained hybrid system.