Theoretical insights into the catalytic mechanism for the oxygen reduction reaction on M 3 (hexaiminotriphenylene) 2 (M = Ni, Cu)

Recently two dimensional (2D) metal-organic frameworks have been successfully used as electrocatalysts, which exhibited a high catalytic activity. Herein, we investigated the catalytic mechanism of the oxygen reduction reaction (ORR) on M (hexaiminotriphenylene) (M (HITP) , M = Ni, Cu) in an acidic medium using the density functional theory (DFT) method. The results indicate that the first electron transfer (ET) to nonadsorbed O is a process of long-range ET on the outer Helmholtz plane (i.e. the ET-OHP mechanism). On the surface of M (HITP) (M = Ni, Cu), both the 2e reduction pathway and the 4e reduction pathway are feasible, while the 2e pathway to form H O is more favorable. In the several competing reactions for the 4e reduction pathway on M (HITP) , the favorable path is OOH* → O* + H O → OH* → H O. Our study provides theoretical guidance for gaining deeper insights into the reaction mechanism of the ORR on M (HITP) (M = Ni, Cu) catalysts.