Fig. 4: Oxidative coupling of anilines.

a Scheme of the catalytic oxidative coupling of anilines to azobenzene. b Conversions of aniline coupling using different catalysts over 24 h at 400 rpm. c TOF values of different catalysts. d Recyclability of h-CoNC. e DFT calculations of the reaction path for aniline coupling to azobenzene on Co-NC and CoNPNC surfaces (C, N, and Co atoms are shown in gray, blue, and pink, respectively). Error bars represent standard deviations of the means.