Tailoring defect-type and ligand-vacancies in Zr(iv) frameworks for CO2 photoreduction. Issue 31 (2nd August 2022) - Wang, Shi-Qing
Abstract : Theoretical calculations in combination with experimental data verified that the type of defects and degree of ligand vacancies in MOFs can tailor the efficiency of CO2 photoreduction. Abstract : The nature and degree of defects can fine-tune the light absorption energy ( E abs ) and charge transfer energy ( E LMCT ) of metal–organic frameworks (MOFs), which are important for photocatalytic reactions. Herein, a series of UiO-66-NH2 with missing-linker (ML)/missing-cluster (MC) defects and different degrees of ligand vacancies were synthesized and utilized to explore their photocatalytic performance of CO2 reduction. The photocatalytic CO yield of UiO-66-NH2 -ML-100 with ML defects reaches 21.3 μmol g −1 h −1, which is 2.2 times that of UiO-66-NH2 -MC-150 with MC. Both experiments and density functional theory (DFT) calculations demonstrate that the nature of MC defects enlarges E abs, while the ligand vacancy changes the coordination environment of Zr(iv ) and lowers E LMCT . More ligand vacancies per metal node lead to smaller E LMCT, which is beneficial for the CO2 photoreduction reaction. This work provides a pathway to boost photocatalytic performance by tailoring the defects of MOFs.