title: Metal-free Ketjenblack incorporated nitrogen-doped carbon sheets derived from gelatin as oxygen reduction catalysts.
abstract: Electrocatalysts facilitating oxygen reduction reaction (ORR) are vital components in advanced fuel cells and metal-air batteries. Here we report Ketjenblack incorporated nitrogen-doped carbon sheets derived from gelatin and apply these easily scalable materials as metal-free electrocatalysts for ORR. These carbon nanosheets demonstrate highly comparable catalytic activity for ORR as well as better durability than commercial Vulcan carbon supported Pt catalysts in alkaline media. Physico-chemical characterization and theoretical calculations suggest that proper combination of graphitic and pyridinic nitrogen species with more exposed edge sites effectively facilitates a formation of superoxide, [O2(ad)](-), via one-electron transfer, thus increasing catalytic activities for ORR. Our results demonstrate a novel strategy to expose more nitrogen doped edge sites by irregular stacked small sheets in developing better electrocatalysts for Zn-air batteries. These desirable architectures are embodied by an amphiphlilic gelatin mediated compatible synthetic strategy between hydrophobic carbon and aqueous water.
authors.affiliation: School of Energy and Chemical Engineering, Ulsan National Institute of Science and Technology (UNIST) , 689-798, Ulsan, South Korea.
authors.forename: Gyutae
authors.initials: G
authors.lastname: Nam
authors.forename: Joohyuk
authors.initials: J
authors.lastname: Park
authors.forename: Sun Tai
authors.initials: ST
authors.lastname: Kim
authors.forename: Dong-bin
authors.initials: DB
authors.lastname: Shin
authors.forename: Noejung
authors.initials: N
authors.lastname: Park
authors.forename: Youngsik
authors.initials: Y
authors.lastname: Kim
authors.forename: Jang-Soo
authors.initials: JS
authors.lastname: Lee
authors.forename: Jaephil
authors.initials: J
authors.lastname: Cho