Defective graphene synergizes with NiO_x nanosheets to facilitate dual-defect-assisted two-electron oxygen reduction

One of the biggest challenges in the electrochemical synthesis of H₂O₂ is the development of high-performance and economical catalysts. In this work, a two-dimensional (2D) composite material consisted with NiO_x nanosheets and defective graphene (DG) (NiO_x@DG) were prepared and showed excellent electrocatalytic performance toward electrosynthesis of H₂O₂ from ORR. Particularly, the NiO_x@DG catalysts present superior activity indicators to physical mixing counterparts (NiO_x-DG), encompassing a high onset potential of 0.78 V, high efficiency and 2e- selectivity over a wide potential range between 0.20−0.60 V (maximal value of 95%). The high-activity of NiO_x@DG can be attributed to the dual-defects (oxygen vacancies on NiO_x and topological defects on DG) induced strong electronic metal–support interaction (EMSI). Such multi-defects collaborative enhancement strategy may provide a promising avenue for the preparation of high-performance catalysts toward application in different reactions.