Photocatalytic and structure evaluation of g-C3N4/carbon microspheres and melam/dimelem intermediates under white LED and UVA-Vis irradiation

Despite the polymeric metal-free graphitic carbon nitride (g-C3N4) has been extensively studied for photo-degradation, intermediate oligomers (melam/dimelem) can be generated during the polymerization process and it is a subject matter. The melem compounds feature active amino groups (-NH2) partially linked to one another, facilitating intermolecular reactions and alteration of the compound's structure. This study evaluated the syn-ergic effect of carbon matrix on the physicochemical and electronic characteristics of g-C3N4 (CN) and melam/ dimelem intermediates compounds by synthesis in situ of chitosan and CN precursors. The g-C3N4 were obtained using urea (U) and melamine (M), denoted as CN/U and CN/M, and the carbon microspheres, denoted as CN/CU and CN/CM. The characterizations suggest C-N sp2-hybridized bonds between the carbon ring from chitosan and the melam/dimelem unit, which may be highly activated either in the visible or UVA regions. An increase of 16% in photocatalytic efficiency for CN/CM material was observed by incorporating chitosan in the g-C3N4 using withe LED light. The carbon microspheres interact synergistically with the bulk g-C3N4 to form two-dimensional planes in which the charge carriers can move freely along the carbon ring structure. The carbon microspheres are an excellent option to separate the photocatalyst easily from the reaction mixture. Additionally, the photo-catalytic degradation mechanism of RhB by carbon microspheres was also proposed.