Titanium metal-organic frameworks for photocatalytic CO conversion through a cycloaddition reaction.

The elevated levels of CO in the atmosphere have been a major concern for environmental scientists. Capturing CO gas and its subsequent conversion to useful organic compounds is one of the avenues that have been extensively studied in the last decade. The photocatalytic cycloaddition of CO is a promising approach for effective CO capture and the production of value-added chemicals such as cyclic carbonates. MOF-901, a titanium-based metal-organic framework with hexagonal layers and imine linkages, was successfully oxidized in this study to MOF-997, incorporating amide linkages using Oxone. Both MOFs displayed remarkable photocatalytic activity in CO cycloaddition under mild conditions, including moderate temperatures and visible light exposure. Particularly noteworthy is MOF-997, exhibiting superior performance with donor-acceptor active sites, achieving a 99.9% yield in catalyzing CO conversion from styrene epoxide to styrene carbonate under solvent conditions.