Super‐Coordinated Nickel N4Ni1O2 Site Single‐Atom Catalyst for Selective H2O2 Electrosynthesis at High Current Densities

Electrochemical production of hydrogen peroxide (H2O2) from O2 on single‐atom catalysts has attracted great attention, yet the quest for robust catalysts is driven by achieving >90 % Faradaic efficiency (FE) under industrial‐relevant current densities (>100 mA cm−2). Herein we synthesize a catalyst that contains single nickel site coordinated by four nitrogen and two oxygen atoms (i.e., N4Ni1O2) via involving carboxyl functionalized multiwall carbon nanotubes as a substrate to provide extra O coordination to the regular NiN4 site. It has a cathodic energy efficiency of approximately 82 % and a H2O2 FE of around 96 % at 200 mA cm−2 current density, outperforming the reported single‐atom catalysts for H2O2 electrosynthesis. A H2O2 electrosynthesis catalyst containing super‐coordinated single nickel sites, that is, ones coordinated by four nitrogen and two O atoms (i.e., N4Ni1O2) on carboxyl functionalized multiwall carbon nanotubes is developed. It gives a 2 e− oxygen reduction reaction (ORR) with a cathodic energy efficiency of approximately 82 % and a H2O2 Faradaic efficiency (FE) of around 96 % at a current density of 200 mA cm−2.