A porphyrin-based COF to reduce CO2 and nitrite in situ for photoelectrochemical catalysis synthesis of urea

Photoelectrocatalytic catalysis of carbon dioxide (CO 2 ) and nitrite (NO 2 − ) direct coupling to synthesise urea (NH 2 CONH 2 ) can effectively avoid the high energy consumption and pollution of the Bosch-Meiser method. COF _PP-TAT was synthesised by hydroformylation of tetrabromophenyl porphyrin (TBPP), amination of trichothecenes (TC), and linking of the two compounds through Schiff base reaction. The comprehensive characterization of COF _PP-TAT showed that has rich pore structure and specific adsorption of CO 2 . These characteristics are favorable for COF to synthesize urea by reducing CO 2 in a green way. COF _PP-TAT exhibited a good CO 2 reduction (CO 2 RR) performance under photoelectrocatalytic (PEC) conditions with the stable production of urea (NH 2 CONH 2 ) at a rate of 0.32 µmol h -1 . That process accompanied by the production of ammonia (NH 3 ), formic acid (HCOOH) and carbon monoxide (CO). The synthesis mechanism was discussed.