Synthesis of g-C3N4 Triazine-structure via modified low-temperature polycondensation of Melamine-Barbiturate

Abstract

A novel supramolecular precursor strategy was developed for the low-temperature synthesis of triazine-structured graphitic carbon nitride (g-C₃N₄). The supramolecular assembly of melamine and barbituric acid enables a significant reduction in the synthesis temperature—from the conventional 550 °C to 350 °C—and shortens processing time to just 60 min. Structural and physicochemical characterization (XRD, FTIR, SEM, and BET) confirms the formation of a triazine-based g-C₃N₄ framework with a specific surface area of 17.6 m²/g and a uniform mesoporous structure (∼3.5 nm). Photocatalytic experiments demonstrate efficient degradation of organic dyes under visible-light irradiation (λ = 365 and 405 nm), indicating the material's enhanced photoactivity. Scanning vibrating electrode technique (SVET) measurements further reveal a clear photoinduced ionic current response under both excitation wavelengths, supporting the presence of defect-associated energy states within the bandgap and confirming the ability of CN-MB-350 to function as a visible-light-responsive semiconductor. The proposed method offers a cost-effective and energy-saving alternative to conventional g-C₃N₄ synthesis and expands the potential for structural tuning of carbon nitride materials via precursor engineering.