What is it about?
Carbon monoxide is widely used to identify catalytic sites on titanium dioxide surfaces: according to literature, very active Ti sites correspond to higher CO vibration frequencies. Here we challenge this model and reveal that the vibration frequency of CO results from a donation/backdonation process, where the oxygen anions of the TiO2 surface act as electron density donors.
Photo by Toa Heftiba on Unsplash
Why is it important?
For the first time, we show that the oxygen atoms of oxide surfaces may affect the properties of a molecule not directly linked to them. This “indirect electron donor” character, is intrinsic to the surface, i.e. it exists independently on the presence of defects, and depends on the specific facet. It can be experimentally detected by monitoring the properties of a probe molecule – in this case, its vibration frequencies. Our finding that oxygen atoms of an oxide surface may act as indirect electron density donors is important because it helps to understand the reactivity of molecules at surfaces.
Read the Original
This page is a summary of: On the Simple Complexity of Carbon Monoxide on Oxide Surfaces: Facet-Specific Donation and Backdonation Effects Revealed on TiO2Anatase Nanoparticles, ChemPhysChem, April 2016, Wiley, DOI: 10.1002/cphc.201600284.
You can read the full text:
Adsorption of carbon monoxide and hydrogen peroxide on TiO2 nanoparticles and TiO2 P25
FT-IR and computational study of carbon monoxide and hydrogen peroxide on TiO2 nanoparticles and nanopowders at high coverage regimes. This article higlights the role of low-coordination Ti sites on TiO2 P25 in the photocatalytic decomposition of hydrogen peroxide H2O2.
Academia page on this article, with supplementary material
ResearchGate page on this article, with supplementary material and figures.
Surface properties of transition metal oxides (Wikipedia)
To collocate our research in context, here is a general, nontechnical article from Wikipedia, dealing with the surface properties of transiton metal oxides. It contains a short description of IR spectroscopy using CO as a probe molecule, where our paper is mentioned.
An infographic explaining this work is available at this blog post
This is my effort to explain in detail the main findings of this article using simple words and examples.
The TiO2-CO bond explained: Slide Presentation
This presentation explains the importance of shape and exposed facets of TiO2 nanoparticles in governing the surface-molecule interactions.
Green open access version of this paper (accepted article)
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