Synthesis of carbon nitride nanocrystals on SBA-15 microparticles by a constant-pressure solvothermal method

C3N4C3N4 nanocrystals were synthesized by the reaction of C3N3Cl3C3N3Cl3 with NaN3NaN3 in DMF through a constant-pressure solvothermal method, using mesoporous silica SBA-15 microparticles (SMP) as the promoter. The key steps in our approach are as follows: (1) by stirring at room temperature for 12 h, the starting materials are adsorbed on SMP, facilitating the reaction of the starting materials and (2) at higher temperature, the intermediates on SMP decompose to form the CNxCNx nanocrystals with higher crystallinity. The crystallinity, morphology and composition of the samples were examined. Both the content of β-C3N4β-C3N4 and the crystallinity of the samples were improved in the presence of SMP. A preliminary model for the formation of CNxCNx involving a six-member ring transition state on SMP is suggested.