Yoon, Ki Ro Hwang, Chang-Kyu Kim, Seung-hoon Jung, Ji-Won Chae, Ji Eon Kim, Jun Lee, Kyung Ah Lim, Ahyoun Cho, Su-Ho Singh, Jitendra Pal Kim, Jong Min Shin, Kihyun Moon, Byung Moo Park, Hyun S. Kim, Hyoung-Juhn Chae, Keun Hwa Ham, Hyung Chul Kim, Il-Doo Kim, Jin Young 2024-01-19T14:30:21Z 2024-01-19T14:30:21Z 2021-10-21 2021-07 1936-0851 https://pubs.kist.re.kr/handle/201004/116785 Oxygen-based electrocatalysis is an integral aspect of a clean and sustainable energy conversion/storage system. The development of economic bifunctional electrocatalysts with high activity and durability during reversible reactions remains a great challenge. The tailored porous structure and separately presented active sites for oxygen reduction and oxygen evolution reactions (ORR and OER) without mutual interference are most crucial for achieving desired bifunctional catalysts. Here, we report a hybrid composed of sheath-core cobalt oxynitride (CoOx@CoNy) nanorods grown perpendicularly on N-doped carbon nanofiber (NCNF). The brushlike CoOx@CoNy nanorods, composed of metallic Co4N cores and oxidized surfaces, exhibit excellent OER activity (E = 1.69 V at 10 mA cm(-2)) in an alkaline medium. Although pristine NCNF or CoOx@CoNy alone had poor catalytic activity in the ORR, the hybrid showed dramatically enhanced ORR performance (E = 0.78 V at -3 mA cm(-2)). The experimental results coupled with a density functional theory (DFT) simulation confirmed that the broad surface area of the CoOx@CoNy nanorods with an oxidized skin layer boosts the catalytic OER, while the facile adsorption of ORR intermediates and a rapid interfacial charge transfer occur at the interface between the CoOx@CoNy nanorods and the electrically conductive NCNF. Furthermore, it was found that the independent catalytic active sites in the CoOx@CoNy/NCNF catalyst are continuously regenerated and sustained without mutual interference during the round-trip ORR/OER, affording stable operation of Zn-air batteries. English AMER CHEMICAL SOC Hierarchically Assembled Cobalt Oxynitride Nanorods and N-Doped Carbon Nanofibers for Efficient Bifunctional Oxygen Electrocatalysis with Exceptional Regenerative Efficiency Article 10.1021/acsnano.0c09905 1 ACS NANO, v.15, no.7, pp.11218 - 11230 ACS NANO 15 7 11218 11230 N scie scopus 000679406500022 2-s2.0-85110552424 Chemistry, Multidisciplinary Chemistry, Physical Nanoscience & Nanotechnology Materials Science, Multidisciplinary Chemistry Science & Technology - Other Topics Materials Science Article REDUCTION REACTION ACTIVE-SITES HIGHLY EFFICIENT NANOWIRE ARRAYS FE-N/C NITROGEN CATALYSTS NITRIDE GRAPHENE OXIDE cobalt oxynitrides carbon nanofibers bifunctional catalysts oxygen reduction reaction oxygen evolution reaction