title: Stable Cobalt Nanoparticles and Their Monolayer Array as an Efficient Electrocatalyst for Oxygen Evolution Reaction.
abstract: Monodisperse cobalt (Co) nanoparticles (NPs) were synthesized and stabilized against oxidation via reductive annealing at 600 °C. The stable Co NPs are active for catalyzing the oxygen evolution reaction (OER) in 0.1 M KOH, producing a current density of 10 mA/cm(2) at an overpotential of 0.39 V (1.62 V vs RHE, no iR-correction). Their catalysis is superior to the commercial Ir catalyst in both activity and stability. These Co NPs are also assembled into a monolayer array on the working electrode, allowing the detailed study of their intrinsic OER activity. The Co NPs in the monolayer array show 15 times higher turnover frequency (2.13 s(-1)) and mass activity (1949 A/g) than the NPs deposited on conventional carbon black (0.14 s(-1) and 126 A/g, respectively) at an overpotential of 0.4 V. These stable Co NPs are a promising new class of noble-metal-free catalyst for water splitting.
authors.affiliation: †Department of Chemistry, Brown University, Providence, Rhode Island 02912, United States.
authors.forename: Liheng
authors.initials: L
authors.lastname: Wu
authors.affiliation: †Department of Chemistry, Brown University, Providence, Rhode Island 02912, United States.
authors.forename: Qing
authors.initials: Q
authors.lastname: Li
authors.affiliation: ‡Department of Chemistry, University of California, Berkeley, California 94720, United States.
authors.forename: Cheng Hao
authors.initials: CH
authors.lastname: Wu
authors.affiliation: †Department of Chemistry, Brown University, Providence, Rhode Island 02912, United States.
authors.forename: Huiyuan
authors.initials: H
authors.lastname: Zhu
authors.affiliation: †Department of Chemistry, Brown University, Providence, Rhode Island 02912, United States.
authors.forename: Adriana
authors.initials: A
authors.lastname: Mendoza-Garcia
authors.affiliation: †Department of Chemistry, Brown University, Providence, Rhode Island 02912, United States.
authors.forename: Bo
authors.initials: B
authors.lastname: Shen
authors.forename: Jinghua
authors.initials: J
authors.lastname: Guo
authors.affiliation: †Department of Chemistry, Brown University, Providence, Rhode Island 02912, United States.
authors.forename: Shouheng
authors.initials: S
authors.lastname: Sun