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submitted on 19.09.2019 and posted on 24.09.2019by Igor Krivtsov, Dariusz Mitoraj, Marina Ilkaeva, Mariana Sardo, Luís Mafra, Christof Neumann, Andrey Turchanin, Chunyu Li, Benjamin Dietzek, Robert Leiter, Johannes Biskupek, Ute Kaiser, Changbin Im, Björn Kirchhoff, Timo Jacob, Radim Beranek
polymeric carbon nitrides (PCN) are well established as promising
photocatalysts for light-driven redox transformations. However, the activity of
these materials is hampered by their low surface area translating into low
concentration of active sites accessible for reactants. Herein, we report, for
the first time, a bottom-up preparation of PCN nanoparticles with a narrow size
distribution (~10±3 nm), which are fully soluble in water showing no gelation
or precipitation over several months, and allow carrying out photocatalysis
under quasi-homogeneous conditions.
The rate of selective (up to 100%) photooxidation of 4-methoxybenzyl alcohol to
4-methoxybenzaldehyde was enhanced by the factor of 6.5 as compared to
conventional solid PCN and was accompanied by simultaneous H2O2
production via reduction of oxygen.
The dissolved photocatalyst can be easily recovered and re-dissolved by simple
modulation of the ionic strength of the medium, without any loss of activity
and selectivity. This work thus establishes a new paradigm of easily operable quasi-homogeneous photocatalysis with PCN,
and opens up a route for other applications in which liquid aqueous operation
or processing of PCN is required.