Unveiling the Complex Configurational Landscape of the Intralayer Cavities in a Crystalline Carbon Nitride

19 August 2021, Version 1
This content is a preprint and has not undergone peer review at the time of posting.


The in-depth understanding of the reported photoelectrochemical properties of the layered carbon nitride, poly(triazine imide)/LiCl (PTI/LiCl), has been limited by the apparent disorder of the Li/H atoms within its framework. To understand and resolve the current structural ambiguities, an optimized one-step flux synthesis (470 oC, 36 h, LiCl/KCl flux) was used to prepare PTI/LiCl and deuterated-PTI/LiCl in high purity. Its structure was characterized by a combination of neutron/X-ray diffraction and transmission electron microscopy. The range of possible Li/H atomic configurations were enumerated for the first time and, combined with total energy calculations, reveals a more complex energetic landscape than previously considered. Experimental data were fitted against all possible structural models, exhibiting the most consistency with a new orthorhombic model (Sp. Grp. Ama2) that also has the lowest total energy. In addition, a new Cu(I)-containing PTI (PTI/CuCl) was prepared with the more strongly scattering Cu(I) cations in place of Li, and which also most closely matched with the partially-disorded structure in Cmc21. Thus, a complex configurational landscape of PTI is revealed to consist of a number of ordered crystalline structures that are new potential synthetic targets, such as with the use of metal-exchange reactions.


Carbon nitrides
Flux synthesis
Poly(triazine imide)

Supplementary materials

Supporting Information
FTIR of PTI/LiCl and d-PTI/LiCl, structural models, tree diagrams of symmetry relationships, helical model of PTI/LiCl, selected area diffraction of Cu-PTI, and SEM images of particles of PTI/LiCl.


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