Proceedings of nanoGe Fall Meeting19 (NFM19)
DOI: https://doi.org/10.29363/nanoge.nfm.2019.335
Publication date: 18th July 2019
The heptazine-based polymeric carbon nitrides are well established as promising photocatalysts for light-driven selective redox transformations. However, the activity of these materials is hampered by their low surface area translating into low concentration of surface active sites accessible for reactants. Herein, we report the synthesis of poly(heptazine imide) materials from melamine at unprecedentedly low temperature of 330 °C. The resulting colloidal nanoparticles are soluble in water, and exhibits a 6.5 times higher reaction rate in selective (up to 100%) photooxidation of 4-methoxybenzyl alcohol to 4-methoxybenzaldehyde and simultaneous H2O2 production by O2 reduction as compared to the conventional polymeric carbon nitride. The solubility of this material allows estimation of a quantum yield of the catalytic photochemical reaction, which is usually complicated for heterogeneous systems, giving a value of ca. 10 % at 365 nm. 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 quasi-homogeneous operation for photocatalysis with carbon nitrides.
DFG - Projektnummer 364549901 – TRR 234