Azobenzene-equipped Covalent triazine polymers for Visible-Light-Driven photocatalytic reduction of CO2 to CH4

Covalent triazine polymers, as large pi conjugated, highly porous, nitrogen riched organic semiconductors, can play a key role in tackling the fuel energy crisis and global warming issues. However, their development in photocatalytic CO2 reduction is still rare. More effective strategies to enhance CO2 reduction activity need to be explored. Herein, different amounts of azobenzene pendants functionalized CTPs: Azo-CTP0, Azo-CTP1, AzomCTP1 and Azo-CTP2, were fabricated for photocatalytic CO2 reduction with Pd loaded. Among them, AzomCTP1 displayed the highest CO2 uptake capacity up to 48.2 cm3 g-1 (2.15 mmol g-1) at 273 K, and the highest CH4 evolution rate in the water system, with selectivity highly up to 97 %. Apart from that, the azobenzene functionalization of Azo-CTP0 could significantly boost the CO2 reduction efficiency by 4 times. Therefore, this study provides a potentially general approach for accurately modifying organic semiconductors to enhance photocatalytic performance.