Understanding Photocatalytic Activity Dependence on Node Topology in Ti-Based Metal-Organic Frameworks

Despite the drive to develop more efficient Ti-based metal- organic framework (MOF) photocatalysts, MIL-125-NH2 is stil l the benchmark, and only a few design principles have been offered to improve photocatalytic performance. Linker functionalization in Ti MOFs has been shown to enable photocatalysis under visible l i g h t by closing the electronic band gap, significant l y improving charge carrier lifetimes. Limited by known Ti-based MOFs, the role of node nuclearity and topology on photocatalytic activity remains unclear. Here, we report a new MOF, ICGM-1, a 3D-connected framework featuring 1D Ti-O rods. Photo-catalytic hydrogen evolution reveals a significant difference in activity, which we attribute solely to node geometry. Using time-resolved spectroscopy and DFT calculations, we ascribe these differences to subtle electronic and geometric properties, pav i n g the way for the development of Ti-MOF photocatalysts.