Rational design of defect metal oxide/covalent organic frameworks Z-scheme heterojunction for photoreduction CO2 to CO

Z-scheme heterostructure consisting of covalent organic frameworks (COF) and inorganic semiconductor pos-sesses tremendous potential for achieving efficient photoreduction of CO2. However, the precise design and rationalization of the interaction between COF and inorganic semiconductors remains a great challenge. Herein, the interaction of different N-sites on T-COF framework with defect TiO2 and stoichiometric TiO2 is investigated by density functional theory. The theoretical analysis suggests that the amine group of T-COF could provide an energetically favored binding site towards defect TiO2. Accordingly, a stable Z-scheme heterostructure with well-defined chemical bonding between Ti3+ and-NH2, and well-engineered geometry configuration through in situ anchoring defect TiO2 on the surface of amine-functionalized T-COF sphere is designed. The obtained hetero-structure exhibits a high CO2-to-CO conversion efficiency, with nearly 100 % CO selectivity and an apparent quantum efficiency of 6.81 % at 365 nm. This work could provide guidance for the rational design of Z-scheme heterostructure photocatalysts for photocatalytic applications in high efficiency.

Automated summary

In this study, the interaction between different nitrogen sites on T-COF framework and defect TiO2 and stoichiometric TiO2 is investigated using density functional theory. It is found that the amine group of T-COF can provide a favorable binding site on defect TiO2. Based on this, a stable Z-scheme heterostructure with well-defined chemical bonding and optimized geometry is designed by anchoring defect TiO2 on the surface of amine-functionalized T-COF sphere. The obtained heterostructure exhibits high CO2-to-CO conversion efficiency with 100% CO selectivity and 6.81% apparent quantum efficiency at 365 nm. This work provides guidance for the rational design of high-efficiency Z-scheme heterostructure photocatalysts for photocatalytic applications.