Synthesis and properties of g-C3N4 bulk and nanosheets derived from thiourea
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https://doi.org/10.15625/2525-2518/18821Keywords:
Graphitic carbon nitride, g-C₃N₄ nanosheet, thiourea precursor, polymerization, photocatalytic materialsAbstract
Graphitic carbon nitride (g-C3N4) is a metal-free polymer semiconductor of interest for visible-light photocatalysis. Here, the g-C3N4 bulk was prepared by thermal polycondensation of thiourea in air (480–550 °C, 2 h; 5 °C min−1). XRD and FTIR analysis confirmed the heptazine/triazine framework, with well-defined (002) and (100) reflections obtained at 520–550 °C, while lower temperatures showed incomplete condensation. Few-layer g-C3N4 nanosheets were then produced by thermal oxidation/exfoliation of the bulk at 500 °C in static air, yielding an expanded, porous morphology observed by FESEM and a weaker (002) peak together with an additional feature near 23°. Optical characterization (UV–Vis DRS and PL) indicated improved light utilization and charge-carrier behavior for the nanosheets: the optical bandgap decreased from 2.750 eV (bulk) to 2.625 eV (nanosheets) and the PL maximum blue-shifted (≈465 → 444 nm) with lower intensity, suggesting suppressed electron–hole recombination. Lorentz deconvolution of PL spectra revealed three main emission centers associated with distinct transition pathways. This simple, solvent-free route using low-cost thiourea provides scalable g-C3N4 bulk and nanosheets for visible-light-driven environmental and energy applications.
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Bộ Giáo dục và Ðào tạo
Grant numbers B2023-BKA-04
