Integration TiO2 nanosheets into defect engineered Zr-based MOF for highly selective and efficient photocatalytic conversion of CO2 to ethane

MOFs have shown promising activities in the photocatalytic reduction of CO2. However, their utility has been primarily limited to C1 products, and high-value C2 chemicals have rarely been achieved due to requirement of a large quantity of electron supplying and the slow kinetic of C-C coupling. In particular, there is a significant scarcity of the research on MOF-catalyzed photo-reduction of CO2 to ethane. To address this challenge, we have developed MOF composites by incorporating TiO2 nanosheets into linker defective Zr-based UiO-67 MOFs (denoted as TiO2(X)@UiO-67). These as-synthesized MOFs, featuring charge-polarized active sites (Zr-O-Ti) at the interface between UiO-67 and TiO2, exhibited a remarkable performance in the photocatalytic conversion of CO2 to ethane under visible light illumination. By screening three isostructural TiO2(X)@UiO-67 MOFs with 1.25 %, 1.75 %, and 2 % Ti wt, we discovered a direct relationship between increasing the level of active bimetallic sites and both efficiency and selectivity. Notably, TiO2(2)@UiO-67 resulted C2H6 productivity of 79.3 mu molh-1g-1 with complete selectivity, which to the best of our knowledge is the most efficient MOF catalytic performance reported to date. This work suggests a promising approach for the design of highly efficient photocatalysts for the CO2 reduction to C2 product.