In Situ Observation of Metal to Metal Oxide Progression: A Study of Charge Transfer Phenomenon at Ru-CuO Interfaces

Alexander Porkovich*, Zakaria Ziadi, Pawan Kumar, Joseph Kioseoglou, Nan Jian, Lin Weng, Stephan Steinhauer, Jerome Vernieres, Panagiotis Grammatikopoulos, Mukhles Sowwan

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

18 Scopus citations


Surface charge and charge transfer between nanoclusters and oxide supports are of paramount importance to catalysis, surface plasmonics, and optical energy harvesting areas. At present, high-energy X-rays and theoretical investigation are always required to determine the chemical state changes in the nanoclusters and the oxide supports, as well as the underlying transfer charge between them. This work presents the idea of using chrono-conductometric measurements to determine the chemical states of the Ru nanoclusters on CuO supports. Both icosahedral and single-crystal hexagonal close-packed Ru nanoclusters were deposited through gas-phase synthesis. To study the charge transfer phenomenon at the interface, a bias was applied to cupric oxide nanowires with metallic nanocluster decoration. In situ conductometric measurements were performed to observe the evolution of Ru into RuOx under heating conditions. Structural elucidation techniques such as transmission electron microscopy, X-ray photoelectron spectroscopy, and Kelvin probe force microscopy were employed to study the corresponding progression of structure, chemical ordering, and surface potential, respectively, as Ru(0) was oxidized to RuOx on the supporting oxide surface. Experimental and theoretical investigation of charge transfer between the nanocluster and oxide support highlighted the importance of metallic character and structure of the nanoclusters on the interfacial charge transfer, thus allowing the investigation of surface charge behavior on oxide-supported catalysts, in situ, during catalytic operation via conductometric measurements.

Original languageEnglish
Pages (from-to)12425-12437
Number of pages13
JournalACS Nano
Issue number11
StatePublished - 26 Nov 2019
Externally publishedYes


  • cupric oxide
  • interface
  • nanoclusters
  • ruthenium
  • surface charge


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