Revealing the exact roles of nitrogen configurations and precise control of the nitrogen configuration in nitrogen-doped graphene (NG) are extremely important for realizing its advanced functions in clean energy technologies. Herein, for the first time, we established that the hydrogen evolution reaction (HER) activities of NG display definite trends due to its nitrogen configurations, which were selectively generated by using layer-structured montmorillonite (MMT) with different layer distances and functions modulated by Co 2+ , Ni 2+ , Na + , and H + ions. We found that among the three types of N, i.e., pyridine, pyrrolic, and quaternary N, quaternary N is the most active one for HER in a metal-free NG catalyst, whereas with an introduction of trace atomic cobalt, the planar (pyridine and pyrrolic) N becomes the better one. In contrast, when trace atomic Ni is involved to replace the Co, the former results in heavily depressed HER activities for the NG catalyst. Density functional theory calculations further revealed that (i) the carbon atoms are highly activated for HER by the nearby quaternary N but not by planar N and (ii) nickel blocks but cobalt promotes the hydrogen adsorption after coordination with planar N, leading to an excellent HER performance.

The precise control of nano‐structure and increase active sites density are of crucial importance for the pyrolyzed Fe‐N−C catalysts′ performance optimization. Herein, the relationship between molecular structures of PANI precursors and the activity for oxygen reduction reaction (ORR) of the derived Fe‐N−C catalysts is investigated. The PANI molecular structure, especially the content of quinoid rings (QR), is controlled by varying molar ratios of ammonium persulfate (APS) to aniline monomers (AN). With the increase of APS/AN ratio from 0.5 to 4, the oxidation degree together with the QR content of PANI increases. Accordingly, the produced catalysts’ morphology experiences an evolution from bulk, nanotube to flower‐like structure. And the ORR activity shows volcano‐relationship with the increase of the QR content in PANI precursors. Specifically, when APS/AN=2.5, the derived PANI with moderate QR content benefits to produce Fe‐N−C catalyst which shows the maximum ORR activity with a half‐wave potential of 0.74 V (vs RHE) in acidic electrolyte among the produced catalysts. Moreover, two opposite effects with the increasing QR content are revealed; i) the QR benefits the Fe coordination and Fe−Nx active sites formation which enhances the activity, and ii) the accompanying formed oligomers decrease the thermal stability and thus decrease the number of active sites.

Three-dimensional graphene sponge (3DG), a bulk collection of numerous suspended individual graphene sheets, could demonstrate an integrated response thousands of times stronger than that of a single sheet under applied external field induction. Herein, for the first time, we find that a two-electrode system assembled with 3DG monoliths shows a high sensitivity to human body induction and infrared radiation. The induced open circuit voltage of the two-electrode system increases by 900 mV in a hand approaching-departing induction. In a closed circuit, fluctuating current is observed flowing backward and forward from one 3DG electrode to another, and it decreased obviously when 3DG electrodes were exposed to infrared radiation. This high sensitivity to electrostatic/ infrared radiation induction is attributed to the high-speed electron redistribution capability of 3DG materials under an applied external electric field or light radiation. These results make 3DG a promising smart material in applications including intelligent monitoring, human body sensors, military protection and life detectors.