Carbon nanotubes with fluorine-rich surface as metal-free electrocatalyst for effective synthesis of urea from nitrate and CO2

In this work, carbon nanotubes with fluorine-rich surface are firstly developed as advanced metal-free catalysts for the electrocatalytic synthesis of urea via co-activation of CO 2 and NO 3 - under ambient conditions. A high yield rate of 6.36 mmol h −1 g cat. −1 with a corresponding Faradaic efficiency of 18.0% was achieved for the urea formation at − 0.65 V vs . reversible hydrogen electrode. Density functional theory calculations indicate the formation of *CO and *NH 2 intermediates is favorable on F-doped C active sites (“C-F 2 ” moieties), facilitating the C-N coupling reaction to form urea. F doped CNTs as the first C-MFEC for electrocatalytic urea synthesis by co-activation of CO 2 and NO 3 - under ambient conditions, which shows the possibilities for coupling reactions even beyond the urea synthesis. • Carbon nanotubes with fluorine-rich surface are firstly developed as advanced metal-free electrocatalysts for urea synthesis. • A urea yield rate up to 6.36 mmol h −1 g cat. −1 was achieved for F -rich CNTs catalyzed urea synthesis from NO 3 - with CO 2 . • “C-F 2 moieties” on F-rich CNTs promote the formation of *CO and *NH 2 intermediates for C-N coupling for urea generation.