Carbon‐based metal‐free catalysts for the hydrogen evolution reaction (HER) are essential for the development of a sustainable hydrogen society. Identification of the active sites in heterogeneous catalysis is key for the rational design of low‐cost and efficient catalysts. Here, by fabricating holey graphene with chemically dopants, the atomic‐level mechanism for accelerating HER by chemical dopants is unveiled, through elemental mapping with atomistic characterizations, scanning electrochemical cell microscopy (SECCM), and density functional theory (DFT) calculations. It is found that the synergetic effects of two important factors—edge structure of graphene and nitrogen/phosphorous codoping—enhance HER activity. SECCM evidences that graphene edges with chemical dopants are electrochemically very active. Indeed, DFT calculation suggests that the pyridinic nitrogen atom could be the catalytically active sites. The HER activity is enhanced due to phosphorus dopants, because phosphorus dopants promote the charge accumulations on the catalytically active nitrogen atoms. These findings pave a path for engineering the edge structure of graphene in graphene‐based catalysts.

Scanning electrochemical cell microscopy with a single barrel micro‐/nano‐pipette (SECCM) was applied to lithium iron phosphate (LiFePO4) composite positive electrodes and an isolated LiFePO4 secondary particle for lithium‐ion batteries. To analyze lithium‐ion (Li+) charge or discharge process on the electrodes using local probe, a pipette filled with LiCl electrolyte solution and Ag/AgCl quasi‐reference counter electrode (QRCE) was used. Both the local electrochemical activities of LiFePO4 on the composite electrodes and a single particle were revealed by SECCM as in‐situ direct measurement of current response‐related Li+ transport from mapping and cyclic voltammogram at confined area by the pipette. The mapping has visualized Li+ deintercalation process from LiFePO4 at +0.65 V (applied between the sample‐QRCE). We show that the SECCM system is a strong analytical tool for a characterization of local Li+ behavior of active electrode materials in lithium‐ion batteries.

Scanning electrochemical cell microscopy with a single barrel nanopipette (nanoSECCM), which is one of scanning electrochemical microscope (SECM) families, is a powerful tool for analyzing electrochemical activities (e.g. redox reaction and lithium-ion (de) intercalation processes) at localized area. A glass nano-pipette is used as a probe of nanoSECCM filled with electrolyte and a reference electrode. As the pipette is in proximity of sample surface, a meniscus is created. Through the meniscus, electrochemical activities can be obtained at localized area on the sample. Further, as the pipette scans the sample surface, electrochemical activities can be also visualized. Our experiments demonstrate that nanoSECCM is applicable to investigation of current response related to lithium-ion transport, redox cycling on various types of electrodes.