Facile Synthesis of g-C₃N₄ for Efficient Photocatalytic Degradation of Rhodamine B
Main Article Content
Abstract
Water pollution caused by Rhodamine B (RhB) underscores the need for efficient photocatalytic degradation methods. In this study, g-C3N4 nanosheets were synthesized via a one-pot thermal polymerization method, with a constant melamine amount and varying NH4Cl content. The obtained g-C3N4 nanosheets exhibited the lateral size of around 0.5 × 2.5 µm and the thickness of about 6-8 nm. g-C3N4 catalysts exhibited high efficiency in the degradation of RhB under ultraviolet (UV) irradiation (365 nm). Within 60 min, RhB degradation reached ~ 99.767% with a rate constant (k) ~ 0.114 min-1. Based on the analytical results, a possible mechanism of photocatalytic degradation was proposed. Its superior performance stems from its numerous active sites and improved surface area, which promoted charge transfer and enhanced redox species generation. Superoxide () and hydroxyl () radicals are the effective agents for photodegrading RhB. This work demonstrates that g-C3N4 nanosheets function as an efficient photocatalyst for removing organic pollutants from wastewater.
Keywords:
g-C3N4, RhB, photocatalyst, UV irradiation
References
1. K. Upendranath, P. Mukherjee, G. V. Megha, K. Manjunath, R. S. Vishwanath, M. Mahanthappa, M. D. Kurkuri, A Multifunctional FeS2/S–g–C3N4 composite for Catalytic Reduction of 4-Nitrophenol and Photocatalytic Degradation of Methylene Blue Dye, Appl. Surf. Sci., Vol. 735, 2026, 166681, https://doi.org/10.1016/j.apsusc.2026.166681
2. B. Liu, Y. Tian, Z. Liu, L. Yi, F. Li, Y.-H. Liu, X. Huang, Innovative Construction of Sulfur-Self-Doped g-C₃N₄/CuFeO₂ S-Scheme Heterojunction for Photocatalytic Removal of Rhodamine B: Mechanism and Detoxification Assessment, J. Photochem. Photobiol. A: Chem., Vol. 479, 2026, 117231, https://doi.org/10.1016/j.jphotochem.2026.117231
3. P. Molaei, F. R. Moghadam, Rapid Thermal Shock Synthesis of Se/g-C3N4 S-Scheme Heterojunctions for Enhanced Photocatalytic Applications, Ceram. Int., Vol. 52, 2026, 17149-17159, https://doi.org/10.1016/j.ceramint.2026.02.301
4. L. N. Thi, T. T. T. Phan, L. N. Tan, T. L. T. Le, L. T. Nguyen, N. T. Hoang, V. Vo, D. Q. Khieu, Activated Carbon/gC3N4/H2O2 System with Enhanced Photocatalytic Activity for Rhodamine-B Degradation under the Visible Light, Environ. Eng. Res., Vol. 30, 2025, 240121, https://doi.org/10.4491/eer.2024.121
5. S. Almotiry, A. A. Algreiby, G. S. Alrebdi, F. M. Al Suqayhi, N. G. sabeel Al Harbi, M. A. Ibrahem, M. A. B. Aissa, Boosting the Photocatalytic Ability of BaZnO by g-C3N4 for Anionic and Cationic Dyes Degradation, Diam. Relat. Mater., Vol. 165, 2026, 113655, https://doi.org/10.1016/j.diamond.2026.113655
6. H.-Q. Luu, M.-T. Pham, Y.-F. Wang, S.-J. You, Enhancing NO Degradation in Visible Light through Plasma-Treated Photocatalytic Substrates Featuring TiO2@g-C3N4 Z-Scheme Structure, Environ. Eng. Res., Vol. 29, 2024, 230560, https://doi.org/10.4491/eer.2023.560
7. C. Chu, Q. Zhu, Z. Pan, S. Gupta, D. Huang, Y. Du, S. Weon, Y. Wu, C. Muhich, E. Stavitski, Spatially Separating Redox Centers on 2D Carbon Nitride with Cobalt Single Atom for Photocatalytic H2O2 Production, PNAS, Vol. 117, 2020, 6376-6382, www.pnas.org/cgi/doi/10.1073/pnas.1913403117
8. Q. Zhu, Y. Shi, Y. Tao, L. Fu, C. Zhang, H. Shang, D. Zhang, G. Li, Binary Heteroatom Dopants Enable Carbon-Based Heterostructures for Efficient Photoelectrocatalytic H2O2 Synthesis in a Wide pH Range, Chem. Eng. J., Vol. 482, 2024, 149066, https://doi.org/10.1016/j.cej.2024.149066
9. Y. Wang, F. Liang, Z. Chen, Piezoelectric Polarization Field Modulation of the Schottky Barrier in Pt/g-C3N4 Heterojunctions: Enhanced Photocatalytic Activity via Hot Electron Transfer, J. Environ. Chem. Eng., Vol. 14, 2026, 122175, https://doi.org/10.1016/j.jece.2026.122175
10. M. Yaqoubi, M. Salavati-Niasari, M. Ghanbari, S-Scheme CuMn2O4/g-C3N4 Heterojunction: Fabrication, Characterization, and Investigation of Photodegradation Potential of Organic Pollutants, Appl. Water. Sci., Vol. 15, 2025, 13, https://doi.org/10.1007/s13201-024-02348-3
11. M. Niknam, M. B. Vandchali, E. Ghasemi, A. Kazemi, N. Yousefi-Limaee, Synthesis and Characterization of a Novel g-C3N4/NiAl-LDH/CeO2 Photocatalyst for Degradation of Rhodamine B, Int. J. Environ. Sci. Technol., Vol. 22, 2025, 4215-4228, https://doi.org/10.1007/s13762-024-06052-2
12. O. V. Alekseeva, V. D. Shibaeva, A. V. Noskov, A. V. Agafonov, Synthesis and Photocatalytic Activity of the TiO2/g-C3N4 Composites: Influence of the TiO2 Particles Morphology (Rod or Spherical) on Degradation of Organic Dyes, Phys. B: Condens. Matter, Vol. 727, 2026, 418302, https://doi.org/10.1016/j.physb.2026.418302
13. S. H. Ammar, A. I. Alyibe, H. J. Hadi, Constructing ZIF-67 over S-Doped g-C3N4 Composites with Enhanced Photocatalytic Degradation Performance toward Organic Pollutants, J. Photochem. Photobiol., Vol. 33, 2026, 100283, https://doi.org/10.1016/j.jpap.2026.100283
14. M. Mahanthappa, M. P. Bhat, A. Alshoaibi, Exploring the Role of Redox-Active Species on NiS-NiS2 Incorporated Sulfur-Doped Graphitic Carbon Nitride Nanohybrid as a Bifunctional Electrocatalyst for Overall Water Splitting, Int. J. Hydrog. Energy, Vol. 84, 2024, 641-649, https://doi.org/10.1016/j.ijhydene.2024.08.220
15. F. Saman, C. H. S. Ling, A. Ayub, N. H. B. Rafeny, A. H. Mahadi, R. Subagyo, R. E. Nugraha, D. Prasetyoko, H. Bahruji, Review on Synthesis and Modification of g-C3N4 for Photocatalytic H2 Production, Int. J. Hydrog. Energy, Vol. 77, 2024, 1090-1116, https://doi.org/10.1016/j.ijhydene.2024.06.212
16. H. Khiar, L. C. Valencia-Valero, N. Barka, A. Puga, (Ag–NiO)/g-C3N4 with Enhanced Photocatalytic Activity for Hydrogen Evolution under Simulated Sunlight, Int. J. Hydrog. Energy, Vol. 91, 2024, 39-49, https://doi.org/10.1016/j.ijhydene.2024.09.377
17. A. V. Zhurenok, P. A. Tkachenko, A. E. Ermoshkina, D. D. Mishchenko, E. E. Aydakov, E. Y. Gerasimov, E. A. Kozlova, Effect of Ni Loading on the Structure and Photocatalytic Performance of g-C3N4-Based Photocatalysts, Inorg. Chem. Commun., Vol. 188, 2026, 116505, https://doi.org/10.1016/j.inoche.2026.116505
18. C. Prasad, K. Sreenivasulu, S. Gangadhara, P. Venkateswarlu, Bio Inspired Green Synthesis of Ni/Fe3O4 Magnetic Nanoparticles Using Moringa Oleifera Leaves Extract: A Magnetically Recoverable Catalyst for Organic Dye Degradation in Aqueous Solution, J. Alloys Compd., Vol. 700, 2017, 252-258, http://dx.doi.org/10.1016/j.jallcom.2016.12.363
19. M. Kaur, A. Kumar, S. M. Siddeeg, M. Selvaraj, S. Gautam, Dual-Functional Ag₃PO₄/CoFe₂O₄/RGO Nanocomposite for Visible-Light-Driven Photocatalytic Degradation of Rhodamine B and Tramadol and Antibacterial Applications, Surf. Interfaces, Vol. 90, 2026, 109194, https://doi.org/10.1016/j.surfin.2026.109194
20. G. H. Shahverdizadeh, K. Seyyedi, A. Mehrizad, R. Majdan-Cegincara, S. Jamshidi, E. Ghasemi, P. Gharbani, M. Farbodi, M. Es' hagi, Recent Insights into g-C3N4 Based Composites for Methylene Blue Photocatalytic Degradation, Results Eng., Vol. 29, 2025, 108595, https://doi.org/10.1016/j.rineng.2025.108595
21. S. Samadder, A. Pandit, M. F. Ahmed, B. Biswas, U. S. Akhtar, T. Paul, M. K. Hossain, N. Sharmin, M. S. Islam, M. E. Halim, Tailoring the Structure and Morphology of Hematite via Zn Doping for Superior Photocatalytic Degradation of Rhodamine B, Open Ceram., Vol. 26, 2026, 100943, https://doi.org/10.1016/j.oceram.2026.100943
22. H. Fazlı, Z. Biyiklioglu, Ö. Kesmez, F. Demir, Synthesis of Water-Soluble Phthalocyanine-Modified Nano TiO2 functional Thin Films and Investigation of Their Photocatalytic Activities against Methylene Blue and Rhodamine B Pollutants, Inorg. Chem. Commun., Vol. 189, 2026, 116653, https://doi.org/10.1016/j.inoche.2026.116653
2. B. Liu, Y. Tian, Z. Liu, L. Yi, F. Li, Y.-H. Liu, X. Huang, Innovative Construction of Sulfur-Self-Doped g-C₃N₄/CuFeO₂ S-Scheme Heterojunction for Photocatalytic Removal of Rhodamine B: Mechanism and Detoxification Assessment, J. Photochem. Photobiol. A: Chem., Vol. 479, 2026, 117231, https://doi.org/10.1016/j.jphotochem.2026.117231
3. P. Molaei, F. R. Moghadam, Rapid Thermal Shock Synthesis of Se/g-C3N4 S-Scheme Heterojunctions for Enhanced Photocatalytic Applications, Ceram. Int., Vol. 52, 2026, 17149-17159, https://doi.org/10.1016/j.ceramint.2026.02.301
4. L. N. Thi, T. T. T. Phan, L. N. Tan, T. L. T. Le, L. T. Nguyen, N. T. Hoang, V. Vo, D. Q. Khieu, Activated Carbon/gC3N4/H2O2 System with Enhanced Photocatalytic Activity for Rhodamine-B Degradation under the Visible Light, Environ. Eng. Res., Vol. 30, 2025, 240121, https://doi.org/10.4491/eer.2024.121
5. S. Almotiry, A. A. Algreiby, G. S. Alrebdi, F. M. Al Suqayhi, N. G. sabeel Al Harbi, M. A. Ibrahem, M. A. B. Aissa, Boosting the Photocatalytic Ability of BaZnO by g-C3N4 for Anionic and Cationic Dyes Degradation, Diam. Relat. Mater., Vol. 165, 2026, 113655, https://doi.org/10.1016/j.diamond.2026.113655
6. H.-Q. Luu, M.-T. Pham, Y.-F. Wang, S.-J. You, Enhancing NO Degradation in Visible Light through Plasma-Treated Photocatalytic Substrates Featuring TiO2@g-C3N4 Z-Scheme Structure, Environ. Eng. Res., Vol. 29, 2024, 230560, https://doi.org/10.4491/eer.2023.560
7. C. Chu, Q. Zhu, Z. Pan, S. Gupta, D. Huang, Y. Du, S. Weon, Y. Wu, C. Muhich, E. Stavitski, Spatially Separating Redox Centers on 2D Carbon Nitride with Cobalt Single Atom for Photocatalytic H2O2 Production, PNAS, Vol. 117, 2020, 6376-6382, www.pnas.org/cgi/doi/10.1073/pnas.1913403117
8. Q. Zhu, Y. Shi, Y. Tao, L. Fu, C. Zhang, H. Shang, D. Zhang, G. Li, Binary Heteroatom Dopants Enable Carbon-Based Heterostructures for Efficient Photoelectrocatalytic H2O2 Synthesis in a Wide pH Range, Chem. Eng. J., Vol. 482, 2024, 149066, https://doi.org/10.1016/j.cej.2024.149066
9. Y. Wang, F. Liang, Z. Chen, Piezoelectric Polarization Field Modulation of the Schottky Barrier in Pt/g-C3N4 Heterojunctions: Enhanced Photocatalytic Activity via Hot Electron Transfer, J. Environ. Chem. Eng., Vol. 14, 2026, 122175, https://doi.org/10.1016/j.jece.2026.122175
10. M. Yaqoubi, M. Salavati-Niasari, M. Ghanbari, S-Scheme CuMn2O4/g-C3N4 Heterojunction: Fabrication, Characterization, and Investigation of Photodegradation Potential of Organic Pollutants, Appl. Water. Sci., Vol. 15, 2025, 13, https://doi.org/10.1007/s13201-024-02348-3
11. M. Niknam, M. B. Vandchali, E. Ghasemi, A. Kazemi, N. Yousefi-Limaee, Synthesis and Characterization of a Novel g-C3N4/NiAl-LDH/CeO2 Photocatalyst for Degradation of Rhodamine B, Int. J. Environ. Sci. Technol., Vol. 22, 2025, 4215-4228, https://doi.org/10.1007/s13762-024-06052-2
12. O. V. Alekseeva, V. D. Shibaeva, A. V. Noskov, A. V. Agafonov, Synthesis and Photocatalytic Activity of the TiO2/g-C3N4 Composites: Influence of the TiO2 Particles Morphology (Rod or Spherical) on Degradation of Organic Dyes, Phys. B: Condens. Matter, Vol. 727, 2026, 418302, https://doi.org/10.1016/j.physb.2026.418302
13. S. H. Ammar, A. I. Alyibe, H. J. Hadi, Constructing ZIF-67 over S-Doped g-C3N4 Composites with Enhanced Photocatalytic Degradation Performance toward Organic Pollutants, J. Photochem. Photobiol., Vol. 33, 2026, 100283, https://doi.org/10.1016/j.jpap.2026.100283
14. M. Mahanthappa, M. P. Bhat, A. Alshoaibi, Exploring the Role of Redox-Active Species on NiS-NiS2 Incorporated Sulfur-Doped Graphitic Carbon Nitride Nanohybrid as a Bifunctional Electrocatalyst for Overall Water Splitting, Int. J. Hydrog. Energy, Vol. 84, 2024, 641-649, https://doi.org/10.1016/j.ijhydene.2024.08.220
15. F. Saman, C. H. S. Ling, A. Ayub, N. H. B. Rafeny, A. H. Mahadi, R. Subagyo, R. E. Nugraha, D. Prasetyoko, H. Bahruji, Review on Synthesis and Modification of g-C3N4 for Photocatalytic H2 Production, Int. J. Hydrog. Energy, Vol. 77, 2024, 1090-1116, https://doi.org/10.1016/j.ijhydene.2024.06.212
16. H. Khiar, L. C. Valencia-Valero, N. Barka, A. Puga, (Ag–NiO)/g-C3N4 with Enhanced Photocatalytic Activity for Hydrogen Evolution under Simulated Sunlight, Int. J. Hydrog. Energy, Vol. 91, 2024, 39-49, https://doi.org/10.1016/j.ijhydene.2024.09.377
17. A. V. Zhurenok, P. A. Tkachenko, A. E. Ermoshkina, D. D. Mishchenko, E. E. Aydakov, E. Y. Gerasimov, E. A. Kozlova, Effect of Ni Loading on the Structure and Photocatalytic Performance of g-C3N4-Based Photocatalysts, Inorg. Chem. Commun., Vol. 188, 2026, 116505, https://doi.org/10.1016/j.inoche.2026.116505
18. C. Prasad, K. Sreenivasulu, S. Gangadhara, P. Venkateswarlu, Bio Inspired Green Synthesis of Ni/Fe3O4 Magnetic Nanoparticles Using Moringa Oleifera Leaves Extract: A Magnetically Recoverable Catalyst for Organic Dye Degradation in Aqueous Solution, J. Alloys Compd., Vol. 700, 2017, 252-258, http://dx.doi.org/10.1016/j.jallcom.2016.12.363
19. M. Kaur, A. Kumar, S. M. Siddeeg, M. Selvaraj, S. Gautam, Dual-Functional Ag₃PO₄/CoFe₂O₄/RGO Nanocomposite for Visible-Light-Driven Photocatalytic Degradation of Rhodamine B and Tramadol and Antibacterial Applications, Surf. Interfaces, Vol. 90, 2026, 109194, https://doi.org/10.1016/j.surfin.2026.109194
20. G. H. Shahverdizadeh, K. Seyyedi, A. Mehrizad, R. Majdan-Cegincara, S. Jamshidi, E. Ghasemi, P. Gharbani, M. Farbodi, M. Es' hagi, Recent Insights into g-C3N4 Based Composites for Methylene Blue Photocatalytic Degradation, Results Eng., Vol. 29, 2025, 108595, https://doi.org/10.1016/j.rineng.2025.108595
21. S. Samadder, A. Pandit, M. F. Ahmed, B. Biswas, U. S. Akhtar, T. Paul, M. K. Hossain, N. Sharmin, M. S. Islam, M. E. Halim, Tailoring the Structure and Morphology of Hematite via Zn Doping for Superior Photocatalytic Degradation of Rhodamine B, Open Ceram., Vol. 26, 2026, 100943, https://doi.org/10.1016/j.oceram.2026.100943
22. H. Fazlı, Z. Biyiklioglu, Ö. Kesmez, F. Demir, Synthesis of Water-Soluble Phthalocyanine-Modified Nano TiO2 functional Thin Films and Investigation of Their Photocatalytic Activities against Methylene Blue and Rhodamine B Pollutants, Inorg. Chem. Commun., Vol. 189, 2026, 116653, https://doi.org/10.1016/j.inoche.2026.116653