title: Intrinsic relationship between enhanced oxygen reduction reaction activity and nanoscale work function of doped carbons.
abstract: Nanostructured carbon materials doped with a variety of heteroatoms have shown promising electrocatalytic activity in the oxygen reduction reaction (ORR). However, understanding of the working principles that underpin the superior ORR activity observed with doped nanocarbons is still limited to predictions based on theoretical calculations. Herein, we demonstrate, for the first time, that the enhanced ORR activity in doped nanocarbons can be correlated with the variation in their nanoscale work function. A series of doped ordered mesoporous carbons (OMCs) were prepared using N, S, and O as dopants; the triple-doped, N,S,O-OMC displayed superior ORR activity and four-electron selectivity compared to the dual-doped (N,O-OMC and S,O-OMC) and the monodoped (O-OMC) OMCs. Significantly, the work functions of these heteroatom-doped OMCs, measured by Kelvin probe force microscopy, display a strong correlation with the activity and reaction kinetics for the ORR. This unprecedented experimental insight can be used to provide an explanation for the enhanced ORR activity of heteroatom-doped carbon materials.
authors.affiliation: Department of Chemistry and ‡School of Energy and Chemical Engineering and KIER-UNIST Advanced Center for Energy, Ulsan National Institute of Science and Technology , 50 UNIST-gil, Ulsan 689-798, Republic of Korea.
authors.forename: Jae Yeong
authors.initials: JY
authors.lastname: Cheon
authors.forename: Jong Hun
authors.initials: JH
authors.lastname: Kim
authors.forename: Jae Hyung
authors.initials: JH
authors.lastname: Kim
authors.forename: Kalyan C
authors.initials: KC
authors.lastname: Goddeti
authors.forename: Jeong Young
authors.initials: JY
authors.lastname: Park
authors.forename: Sang Hoon
authors.initials: SH
authors.lastname: Joo