title: Asymmetric Volcano Trend in Oxygen Reduction Activity of Pt and Non-Pt Catalysts: In Situ Identification of the Site-Blocking Effect.
abstract: Proper understanding of the major limitations of current catalysts for oxygen reduction reaction (ORR) is essential for further advancement. Herein by studying representative Pt and non-Pt ORR catalysts with a wide range of redox potential (Eredox) via combined electrochemical, theoretical, and in situ spectroscopic methods, we demonstrate that the role of the site-blocking effect in limiting the ORR varies drastically depending on the Eredoxof active sites; and the intrinsic activity of active sites with low Eredoxhave been markedly underestimated owing to the overlook of this effect. Accordingly, we establish a general asymmetric volcano trend in the ORR activity: the ORR of the catalysts on the overly high Eredoxside of the volcano is limited by the intrinsic activity; whereas the ORR of the catalysts on the low Eredoxside is limited by either the site-blocking effect and/or intrinsic activity depending on the Eredox.
authors.affiliation: Department of Chemistry and Chemical Biology, Northeastern University , Boston, Massachusetts 02115, United States.
authors.forename: Jingkun
authors.identifier: 0000-0003-1699-3089
authors.initials: J
authors.lastname: Li
authors.affiliation: Department of Chemistry and Chemical Biology, Northeastern University , Boston, Massachusetts 02115, United States.
authors.forename: Amell
authors.initials: A
authors.lastname: Alsudairi
authors.affiliation: Shanghai Electrochemical Energy Devices Research Center, Department of Chemical Engineering, Shanghai Jiao Tong University , Shanghai 200240, China.
authors.forename: Zi-Feng
authors.initials: ZF
authors.lastname: Ma
authors.affiliation: Department of Chemistry and Chemical Biology, Northeastern University , Boston, Massachusetts 02115, United States.
authors.forename: Sanjeev
authors.initials: S
authors.lastname: Mukerjee
authors.affiliation: Department of Chemistry and Chemical Biology, Northeastern University , Boston, Massachusetts 02115, United States.
authors.forename: Qingying
authors.initials: Q
authors.lastname: Jia