Ultralow Fe instigated defect engineering of hierarchical N–Porous carbon for highly efficient electrocatalysis

Abstract

Multifunctional electrocatalysts with excellent performance are highly desirable for new energy technologies. An electrocatalyst is synthesized using a straightforward two-step approach, whereby ultralow doping (0.06 wt%, Fe) and a heteroatom (N) generate defects. A defect-induced active sites accompanied by porous channels enables high catalytic activity and durability for oxygen evolution reaction (OER) and hydrogen evolution reaction (HER). Experiments show that such defects enhance reaction kinetics and promote electrochemical activity with an OER overpotential of 248 mV at 10 mA cm−2 and a Tafel value of 85 mV dec−1. Through density functional theory, carbon matrix defects are observed to be beneficial for OER intermediates adsorption–desorption process. Thus, an avenue for engineering defects has opened for highly efficient multifunctional electrocatalysts by incorporating non-noble metal atoms into a carbon matrix at ultralow loading levels.