Oxygen Species on Nitrogen-Doped Carbon Nanosheets as Efficient Active Sites for Multiple Electrocatalysis

Designing and synthesizing nanomaterials with high coverages of active sites is one of the most-pivotal factors in the construction of state-of-the-art electrocatalysts with high performance. Herein, we proposed a facile in situ templated method for the fabrication of oxygen-species-modified nitrogen-doped carbon nanosheets (O–N–CNs). The epoxy oxygen and ketene oxygen combined with graphitic-nitrogen defects in O–N–CNs gave more active sites for the oxygen-reduction reaction (ORR) and the oxygen-evolution reaction (OER), as proven via theoretical and experimental results, while the carbonyl-oxygen and epoxy-oxygen species showed more efficient electrocatalytic activity for the hydrogen evolution reaction (HER). Hence, the O–N–CNs showed highly active electrocatalytic performance toward ORR, OER, and HER. More importantly, the superior multifunctional electrocatalytic activity of O–N–CNs allowed their use in the construction of Zn-air batteries to power the corresponding water-splitting cells. This work c...