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X‑ray Photochemistry of Prussian Blue Cellulosic Materials: Evidence for a Substrate-Mediated Redox Process
journal contribution
posted on 2015-07-28, 00:00 authored by Claire Gervais, Marie-Angélique Languille, Giulia Moretti, Solenn RéguerBeside its promising applications
in the design of multifunctional
materials, batteries and biosensors, the pigment Prussian blue is
still studied in heritage science because of its capricious fading
behavior due to a complex light-induced redox mechanism. We studied
model heritage materials composed of Prussian blue embedded into a
cellulosic fiber substrate by means of X-ray absorption near-edge
spectroscopy. Significant X-ray radiation damage was observed and
characterized. X-ray radiation induced first a reduction of Prussian
blue, in a similar way to what visible light does, followed by a complete
degradation of the pigment and the formation of iron(III) oxyhydroxide.
We took advantage of this X-ray photochemistry to investigate in depth
the redox behavior of Prussian blue. We could particularly demonstrate
that the rate, extent, and quality of Prussian blue photoreduction
can be tuned by modifying the pH and alkali cation content of the
cellulosic substrate. The present study represents a step further
in the understanding of Prussian blue heritage materials from an electrochemical
viewpoint and provides evidence of substrate-mediated photochemistry
applicable to a wider class of Prussian blue composite materials.