EUROPEAN CONGRESS AND EXHIBITION ON ADVANCED MATERIALS AND PROCESSES - EUROMAT 2021

Porous organic polymers are at the forefront of many research efforts owing to their broad chemistries and excellent textural properties. One promising family of such materials is hypercrosslinked polymers (HCPs), a set of low-cost nanoporous networks. These polymers are typically prepared by the crosslinking of aromatic compounds using simple Friedel–Crafts chemistry, allowing broad ‘bottom-up’ design for a fraction of the cost of many leading porous materials.

The design of robust, high-performance photocatalysts is key for the success of solar fuel production via CO2 conversion. We recently reported the first examples of HCPs as the sole active material in the selective photocatalytic reduction of CO2 to CO, requiring only sacrificial H2O for visible-light-driven photocatalysis. HCPs can significantly outperform the benchmark material TiO2 P25 and achieve gaseous product selectivities of over 95 %. We hypothesise that superior H2O adsorption capacities of these HCPs facilitate access to photoactive sites, improving photocatalytic conversion rates when compared to sacrificial H2. These networks are an intriguing set of organic photocatalysts, displaying no long-range order or extended pi-conjugation. The as-synthesised networks are the sole photocatalytic component, requiring no added co-catalyst doping or photosensitiser, representing a highly versatile and exciting platform for solar-energy conversion.

Given the versatility of HCP synthesis, an unfathomable number of design iterations are possible, presenting a huge opportunity to use this work as a foundation for organic photocatalyst engineering. Furthermore, HCPs do not contain, nor require, rare-earth metals, presenting significant sustainability benefits. This approach equips researchers with a powerful new set of photocatalyst design tools.