Fabrication of G-C3N4 Nanosheets Through Solvent-Assisted Synthesis for Improved Photocatalytic Applications

Graphitic carbon nitride (g-C₃N₄) has emerged as a photocatalyst material of interest due to its strong visible-light activity, good stability, and tunable electronic properties, making it attractive for environmental and energy-related applications. However, producing high quality exfoliated g-C₃N₄ nanosheets using a simple and low-cost technique remains challenging. In this work, bulk g-C₃N₄ was synthesized through the thermal polymerization of melamine and subsequently exfoliated ultrasonically in either deionized water (CN-DI) or isopropanol (CN-IPA). Different exfoliation pathways including thermal, chemical, and one-step methods were examined to determine their impact on the nanosheets’ structural and photocatalytic characteristics. X-ray diffraction (XRD) confirmed that the crystalline structure of g-C₃N₄ remained intact after exfoliation. Transmission electron microscopy (TEM) and scanning electron microscope (SEM) analyses showed the formation of ultrathin nanosheet-like structures with a layered morphology. The ultrathin nanosheets displayed broadened interlayer spacing, as further supported by UV-Vis and photoluminescence (PL) results that showed a noticeable red shift, enhanced light absorption, and reduced electron-hole recombination in CN-DI and CN-IPA compared with bulk g-C₃N₄. These improvements primarily stem from increased surface area, better charge separation, and more effective photon utilization achieved through ultrasonic exfoliation. Photocatalytic tests additionally revealed that both CN-DI and CN-IPA achieved more than 60% degradation of organic dyes under UV illumination. Overall, the findings highlight a straightforward, green, and scalable approach for producing high-performance g-C₃N₄ nanosheets suitable for wastewater purification under UV-light environment.