Photocatalytic water oxidation by very small cobalt domains on a silica surface

Hyun Seo Ahn, Junko Yano, T. Don Tilley

Research output: Contribution to journalArticle

35 Citations (Scopus)

Abstract

Small domains of cobalt on silica (CoSBA) were prepared by the reaction of Co[N(SiMe3)2]2 and SBA-15, resulting in a range of surface structures as the cobalt loading varied from 0.27 to 5.11 wt%. X-ray absorption spectroscopy (XAS) was employed to characterize these surface structures, which range from single-site cobalt atoms to small clusters of Co3O4. The CoSBA materials exhibit photochemical water oxidation catalysis, revealing distinct catalytic activities associated with characteristic types of surface structures that are dominant in particular concentration regimes. The catalytic turnover frequency for water oxidation of an isolated single-site cobalt atom (0.0143 s-1) is much greater than that observed for a surface atom of a small cluster Co3O4 on silica (0.0006 s-1). The CoSBA catalysts were recyclable for more than seven catalytic cycles (>200 turnovers) with additional sacrificial oxidant, and no leaching of cobalt was observed. Post-catalytic analysis of CoSBA by XAS revealed that the cobalt atoms were partially oxidized to Co 3+, without exhibiting significant surface migration and aggregation of cobalt atoms.

Original languageEnglish
Pages (from-to)3080-3087
Number of pages8
JournalEnergy and Environmental Science
Volume6
Issue number10
DOIs
Publication statusPublished - 2013 Oct 1

Fingerprint

Cobalt
cobalt
Silicon Dioxide
silica
Silica
oxidation
Oxidation
Water
Atoms
Surface structure
X ray absorption spectroscopy
water
atomic absorption spectroscopy
X-ray spectroscopy
turnover
catalysis
Oxidants
oxidant
Catalysis
Leaching

All Science Journal Classification (ASJC) codes

  • Environmental Chemistry
  • Renewable Energy, Sustainability and the Environment
  • Nuclear Energy and Engineering
  • Pollution

Cite this

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Photocatalytic water oxidation by very small cobalt domains on a silica surface. / Ahn, Hyun Seo; Yano, Junko; Tilley, T. Don.

In: Energy and Environmental Science, Vol. 6, No. 10, 01.10.2013, p. 3080-3087.

Research output: Contribution to journalArticle

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