A high-loading Fe-pyridinic N bonding structure is prepared through a one-step thermal-reduction method. In the process, activated carbon matrix stimulates the halfway and complete reduction of Fe³⁺, forming Fe-pyridinic N and single Fe atom.

Carbon‐based materials have been found to accelerate the sluggish kinetic reaction and are largely subject to the overall Zn‐air batteries (ZABs) property, while their full catalytic mechanism is still not excavated because of the indistinct internal structure and immature in‐situ technology. Up to now, systematic methods have been utilized to study and design promising high‐performance carbon‐based catalysts. To resolve the real active units and catalytic mechanism, developing molecular catalyst is a significant strategy. Herein, the review will initiate to briefly introduce the working principle and composition of ZABs. An important statement is correspondingly provided about the typical structure and catalytic mechanisms for the air cathode material. It also presents the tremendous endeavors on the catalytic performance and stability of carbon‐based material. Furthermore, combined with theoretical calculation, the self‐defined active sites are analyzed to understand the catalytic character, where the molecular catalyst is subsequently summarized and discussed through highlighting the unambiguous and controllable structure, in the hope of surfacing the optimum catalyst. Building on the fundamental understanding of carbon‐based and molecular catalysts, this review is expected to provide guidance and direction toward designing future mechanistic studies and ORR electrocatalysts.

Doping heteroatom, an effective way to enhance the electrochemical performances of graphene, has received wide attention, especially related to nitrogen. Alternating voltage electrochemical exfoliation, as a low cost and green electrochemical approach, has been developed to construct in-situ N-doped graphene (N-Gh) material. The N-Gh presents a much higher capacity than that of pure graphene prepared via the same method, which might be attributed to the introduction of nitrogen, which has much more effects and a disordered structure. As-prepared N-Gh exhibits a low O/C ratio that is helpful in maintaining high electrical conductivity. And the effects and disorder structure are also conductive to reduce the overlaps of graphene layers. A symmetric supercapacitor assembled with N-Gh electrodes displays a satisfactory rate behavior and long cycling stability (92.3% retention after 5,000 cycles).