Gas-induced modulation of carbon nitride morphology through a green one-step calcination strategy

Considering that graphitic carbon nitride (g-C3N4) has been employed as a photocatalytic material, multidimensional morphology modulation is of particular importance as the most effective method for increasing the specific surface area and enhancing the catalytic properties among all modifications. This work focuses on the development of a facile and green synthesis strategy for multidimensional carbon nitride, and the catalytic properties of the prepared materials were evaluated by utilizing Cr(vi) reduction as a model reaction. Ultimately, following the optimization of the preparation conditions such as calcination temperature and heating rate, the sample TCN-5, a conical tubular carbon nitride material with sea urchin-like stacking, was fabricated through the simple one-step calcination of melamine. The material exhibits the most optimal photocatalytic activity owing to its distinctive one-dimensional structure and exhibits enhanced light-sensing and mass transfer capabilities. Furthermore, the theory of gas-induced modulation in the morphology and structure of carbon nitride is further proposed. Briefly, the ammonia gas produced by precursor polymerisation affects the molecular structure at the microscopic level by altering the particle stacking density and exerts an influence on the morphology of the sample at the macroscopic level through the pushing and stripping effect of the gas. This work provides substantial evidence and theoretical guidance for the optimized modification of carbon nitride, presenting a new way for developing advanced carbon nitride materials and beyond.