title: Probing the surface of transition-metal nanocrystals by chemiluminescence.
abstract: We propose a simple chemiluminescence (CL) method for investigation of the surface of Co-based nanocrystals (NCs). Using a combination of CL and spin-trap electron paramagnetic resonance techniques, we systematically studied the generation of reactive oxygen species (ROS) at the surface of differently sized CoPt(3) spherical NCs and CoPt(3)/Au nanodumbbells. We have shown that differently sized CoPt(3) NCs can promote the formation of ROS and as a result can lead to the oxidation of luminol accompanied by the emission of the light. CL allows monitoring the stability of transition-metal-based NCs against oxidation and dissolution. We found by CL that cobalt ions slowly leach from the surface of CoPt(3) NCs even under very mild conditions; however, the amount of the leached cobalt ions does not exceed the maximal concentration of cobalt at the NC surface indicating that only surface atoms can go into solution.
authors.affiliation: Center for Nanoscale Materials, Argonne National Laboratory, Argonne, Illinois 60439, USA.
authors.forename: Galyna
authors.initials: G
authors.lastname: Krylova
authors.forename: Nada M
authors.initials: NM
authors.lastname: Dimitrijevic
authors.forename: Dmitri V
authors.initials: DV
authors.lastname: Talapin
authors.forename: Jeffrey R
authors.initials: JR
authors.lastname: Guest
authors.forename: Holger
authors.initials: H
authors.lastname: Borchert
authors.forename: Arun
authors.initials: A
authors.lastname: Lobo
authors.forename: Tijana
authors.initials: T
authors.lastname: Rajh
authors.forename: Elena V
authors.initials: EV
authors.lastname: Shevchenko