Efficient nonprecious‐metal oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) electrocatalysts are key for the commercial viability of fuel cells, metal–air batteries, and water‐splitting systems. Thus, high‐performance ORR and OER electrocatalysts in acidic electrolytes are needed to support high‐efficiency proton exchange membrane (PEM)‐based systems. Herein, we report a new approach to design and prepare an ultrathin N‐doped holey carbon layer (HCL) on a graphene sheet that exhibits outstanding bifunctional ORR/OER activities in both alkaline and acidic media. The edge sites of HCL are utilized to achieve selective doping of highly active pyridinic‐N. The sandwiched graphene sheet provides mechanical support, stabilizes HCL structure and promotes charge transfer. The synergetic effect of the catalyst structure overcomes the drawbacks of holey graphene approaches. The resulting ORR and OER performances are equal to or better than the top‐ranked electrocatalysts.

Graphene-based materials have been widely studied to overcome the hurdles of Li-S batteries, but suffer from the low adsorptivity to polar polysulfide species, slow mass transport of Li + ions and severe irreversible agglomeration. Herein, via a one-step scalable calcination process, we successfully synthesized a holey Fe, N co-doped graphene (HFeNG) to address these problems. Diverging by the holey structures, the Fe atoms are anchored by four N atoms (Fe-N 4 moiety) or two N atoms (Fe-N 2 moiety) localized on the graphene sheets and edge of holes, respectively, which was confirmed by Xray absorption spectroscopy and the density functional theory calculations. The unique holey structures This article is protected by copyright. All rights reserved.2 not only promote the mass transport of lithium ions, but also prohibit the mobile polysulfides across these additional channels via strong adsorption forces of Fe-N 2 moiety at the edges. The as-obtained HFeNG delivered a high rate capacity of 810 mAh g -1 at 5 C and a stable cycling performance with the capacity decay of 0.083% per cycle at 0.5 C. The concept of holey structure and introduction of polar moieties could be extended to other carbon and 2D nanostructures for energy storage and conversion devices such as supercapacitors, alkali-ion batteries, metal-air batteries and metal-halogen batteries.

Ni– and Co–porphyrin multilayers on reduced graphene oxide (rGO) sheets are reported as novel bifunctional catalysts for the oxygen evolution reaction (OER) and the oxygen reduction reaction (ORR).