Background
Conventional porous framework materials — MOFs, COFs, and HOFs — have diverse applications in carbon capture, battery electrodes, supercapacitors, and solar panels, but their industrialization faces bottlenecks such as poor water stability and insulating nature. Herein, we report the scalable and sustainable synthesis of stable phosphate-HOFs and COFs. The HOFs and COFs described here are simply organic linkers cross-linked by hydrogen bonds and P-O-P bondes respectively, enabling sustainable synthesis, high chemical stability and recyclability, and new material properties beyond those of conventional MOFs, COFs, and HOFs.
Technical Description
The central component is an organic linker containing at least one hydroxyl group and a tetrahedrally coordinated central atom (e.g. R-PO3H2). Porosity can be tuned to surface areas above 3000 m2/g. Band gaps typically range from 1.4–1.7 eV, depending on linker design, and conductivities can range between 10-10 to 102 S/cm. Synthesis can be achieved using versatile linkers with V-, L-, T-, Y-, X-shaped geometries. Syntheses of HOFs proceed by crystallizing organic linkers in polar or non-polar solvents, while COFs are obtained via single step condensation of linkers without solvents. HOF thin films form easily and can be converted into more stable COF phases upon heating.
see also Nature Communications 15, 7862 (2024) https://doi.org/10.1038/s41467-024-51950-1
Possible Applications
CO2 capture, Proton exchange membrane fuel cells, Electrode material in electrochemical double-layer capacitors and supercapacitors Photoactive layers in solar cells and other semiconductor applications (e.g. flexible electronics, printed electronics, printed conductors, thin-film transistors) Components in active and passive electronic devices and as printing materials for electronic components
Demonstration of CO2 capture in a porphyrin based polyphosphonate-COF (© HHU / Gündog Yücesan)
