Molecular Doping of Electrochemically Prepared Triazine-based Carbon Nitride by 2,4,6-Triaminopyrimidine for Improved Photocatalytic Properties

The copolymerization of melamine with 2,4,6-triaminopyrimidine (TAP) in an electrochemical induced polymerization process leads to the formation of molecular doped poly (triazine imide) (PTI). The polymerization is based on the electrolysis of water and evolving radicals during this process. The incorporation of TAP is shown by techniques such as elemental analysis, FTIR and NMR spectroscopy and powder x-ray diffraction (XRD), and it is shown that the carbon content can be tuned by the variation of the molar ratio of the two precursors. This incorporation of TAP directly influences the electronic structure of PTI and as a result a red-shift can be observed in UV-Vis spectroscopy. The smaller bandgap and the increased absorption in the visible range lead to improved photocatalytic properties. In dye degradation experiments it was possible to observe an increase of the rate of the degradation of methylene blue (MB) by a factor of 4 in comparison to undoped PTI or 7 if compared to melon.