Single-crystalline melem (C₆N₁₀H₆) nanorods: A novel stable molecular crystal photocatalyst with modulated charge potentials and dynamics

It is still challenging to control the crystallization and morphologies of molecular crystal nanostructures with excellent photocatalytic activities. In this study, single-crystalline melem (C₆N₁₀H₆) nanorods (MNRs) were prepared by a facile thermal polymerization route under a flowing argon atmosphere. Compared with the bulk melem counterpart and g-C₃N₄, the MNRs exhibited substantially improved efficiency and stability towards the photodegradation of diverse organic pollutants including methyl orange, rhodamine B, and methylene blue. Moreover, the average photocatalytic hydrogen evolution rate of MNRs was about 2.6 folds higher than that of bulk melem under the same conditions. The enhanced photocatalytic redox performance of MNRs arises from the single-crystal nature and novel one-dimensional (1D) nanorod morphology, contributing to elevated conduction band potentials and promoting charge transport dynamics. This study not only reports single-crystalline melem 1D nanostructures as novel highly efficient and stable molecular-crystal photocatalysts, but also reveals the important roles of synergetic tuning of charge potentials and dynamics in enhancing the photocatalytic activity of molecular-crystal photocatalysts.