10.57647/jnsc.2025.1505.21

Dimensionality-Driven CQD/TiO2-g-C3N4 Ternary Composites for Boosting Photocatalytic and PEC Performance

PDF
  • Tahira Bano1,
  • Shamaila Sajjad*1,
  • Sajjad Ahmed Khan Leghari2,
  • Maria Murtaza1,
  • Rehana Riaz1,
  1. Faculty of Sciences, International Islamic University, H-10, Islamabad, 44000, Pakistan
  2. Pakistan Institute of Engineering and Applied Sciences, Islamabad, Pakistan

Received: 20-07-2025

Revised: 28-08-2025

Accepted: 02-10-2025

Published in Issue 20-10-2025

Copyright (c) 2025 Tahira Bano, Shamaila Sajjad, Sajjad Ahmed Khan Leghari, Maria Murtaza, Rehana Riaz (Author)

Creative Commons License

This work is licensed under a Creative Commons Attribution 4.0 International License.

How to Cite

Bano, T., Sajjad, S., Leghari, S. A. K., Murtaza, M., & Riaz, R. (2025). Dimensionality-Driven CQD/TiO2-g-C3N4 Ternary Composites for Boosting Photocatalytic and PEC Performance. Journal of Nanostructure in Chemistry, 15(5 (October 2025). https://doi.org/10.57647/jnsc.2025.1505.21
Crossref
Scopus
Google Scholar
Europe PMC

PDF views: 40

Abstract

Photocatalysis and photoelectrochemical (PEC) water splitting are hindered by challenges such as rapid electron-hole recombination, limited visible light absorption, and inefficient charge transport. To overcome these limitations, a ternary composite CQD/TiO₂-g-C₃N₄ was engineered by combining 0D carbon quantum dots (CQDs), 1D TiO₂ nanorods, and 2D g-C₃N₄ nanosheets. This multidimensional structure significantly improves charge separation and transfer that enhances both photocatalytic and PEC efficiency. X-ray diffraction confirmed successful integration of TiO₂ and g-C3N4, with crystallite sizes ranging from 8.1 to 9.3 nm. SEM and TEM analyses showed uniform dispersion of TiO₂ nanorods on g-C₃N₄ sheets, while CQDs (~5–6 nm) were attached to surface, establishing strong interfacial contact for efficient charge movement. UV-vis exhibited a redshift, indicating a narrower band gap, and PL analysis showed reduced electron-hole recombination. Under visible light, composite with 15.0 mL CQD displayed excellent photocatalytic activity, achieving 96.0% degradation of mixed dyes (MO + BPB) with clear linear degradation indicating consistant reaction rate and delivering a high PEC photocurrent density (~33 mA·cm⁻²). CQDs enhance charge separation and lower band gap while multidimension (0D–1D–2D) structure boosts charge transfer. The 0D–1D–2D architecture enhances charge mobility and light utilization, making this material highly effective for environmental cleanup and sustainable energy applications.

Keywords

  • Dimensionalities,
  • Synergistic role,
  • CQDs,
  • Ternary composite,
  • 2D g-C3N4
PDF

References

  1. Jabeen, H., Haider, R. S., Sajjad, S., Leghari, S.A.K., Noor, N.,. Amin, M. A., and Ibrahim. M. M., Advances in modifications of Ag/g-C₃N₄ for stable and effective photoanode for OER. Opt Mater 145, 114376 (2023)
  2. Gao, Q., Wang, M., Zhu, Y., Chai, Y., & Liu, B. Facile Construction of CdS/g-C3N4 Photocatalyst for Enhanced Removal of Methyl Orange. Water, Air, & Soil Pollution. 236(7), 427 (2025).
  3. Leghari, S.A.K., Sajjad, S., Zhang, J. A time saving and cost effective route for metal oxides activation. RSC Adv. 4, 5248–5253 (2014)
  4. Yousaf, Z., Sajjad, S., Leghari, S.A.K., ElBahy, Z. Influence of integrated nitrogen functionalities in nitrogen doped graphene modified WO₃ functional visible photocatalyst. J Environ. Chem. Eng. 9, 106746 (2021)
  5. Guo, R.T., Wang, J., Bi, Z.-X., Chen, X., Hu, X., Pan, W.G. Recent advances and perspectives of g–C₃N₄–based materials for photocatalytic dyes degradation. Chemosphere. 287, 132132 (2022)
  6. Thambiliyagodage, C., Kumara, A., Jayanetti, M., Usgodaarachchi, L., Liyanaarachchi, H., Lansakara, B. Fabrication of dual Z-scheme g-C₃N₄/Fe₂TiO₅/Fe₂O₃ ternary nanocomposite using natural ilmenite for efficient photocatalysis and photosterilization under visible light. Appl. Surf. Sci. Adv. 12, 100337 (2022)
  7. Qamar, M.A., Javed, M., Shahid, S., Shariq, M., Fadhali, M.M., Ali, S.K., Khan, M.S. Synthesis and applications of graphitic carbon nitride (g-C₃N₄) based membranes: A review. Heliyon. 9, 12685 (2023)
  8. an, J., You, M., Chi, C., Dong, Z., Wang, B., Zhu, M., Li, C. The two dimension carbon quantum dots modified porous g-C3N4/TiO2 nano-heterojunctions for visible light hydrogen production enhancement. Int J Hydrogen Energy. (13), 6586-6593 (2018)
  9. Panimalar, S., Uthrakumar, R., Selvi, E. T., Gomathy, P., Inmozhi, C., Kaviyarasu, K., & Kennedy, J. Studies of MnO₂/g-C₃N₄ heterostructure efficient of visible light photocatalyst for pollutants degradation by sol-gel technique. Int J Hydrogen Energy. 45, 11501–11510 (2020).
  10. Nemiwal, M., Zhang, T. C., & Kumar, D. Recent progress in g-C₃N₄, TiO₂ and ZnO based photocatalysts for dye degradation: Strategies to improve photocatalytic activity. Sci.Total. Environ.767, 144896 (2021)
  11. Liyanaarachchi, H., Thambiliyagodage, C., Liyanaarachchi, C., Samarakoon, U. Efficient photocatalysis of Cu doped TiO₂/g-C₃N₄ for the photodegradation of methylene blue. Arabian J Chem. 16, 104749 (2023)
  12. Zhu, M., Zhai, C., Sun, M., Hu, Y., Yan, B., & Du, Y. Ultrathin graphitic C₃N₄ nanosheet as a promising visible-light-activated support for boosting photoelectrocatalytic methanol oxidation. Appl Catal B Environ. 203, 108–115 (2017).
  13. Kong, L., Wang, J., Mu, X., Li, R., Li, X., Fan, X., Sun, M. Porous size dependent g-C₃N₄ for efficient photocatalysts: regulation syntheses and physical mechanism. Mater Today Energy. 13, 11–21 (2019)
  14. Wang, L., Wang, K., He, T., Zhao, Y., Song, H., & Wang, H. Graphitic carbon nitride-based photocatalytic materials: preparation strategy and application. ACS Sustainable Chemistry & Engineering. 8(43), 16048-16085 (2020)..
  15. Karimkhani, S., Derakhshi, P., Aberoomand Azar, P., Sheikh-Al-Eslamian, S.M. Facile, fast, and green preparation of high-purity and quality silica nanoparticles using a handmade ball mill: comparison with the sol–gel method. J Nanostruct Chem. 14, 369–381 (2024)
  16. Abbas, S., Uzair, B., Sajjad, S., Leghari, S.A.K., Noor, S., Khan Niazi, M.B., Farooq, I., Iqbal, H. Dual-Functional Green Facile CuO/MgO Nanosheets Composite as an Efficient Antimicrobial Agent and Photocatalyst. Arab J Sci Eng. 47, 5895-5909 (2022.
  17. Noor, S., Sajjad, S., Leghari, S.A.K., Flox, C., Ahmad, S. Competitive role of nitrogen functionalities of N doped GO and sensitizing effect of Bi₂O₃ QDs on TiO₂ for water remediation. J Environ Sci. 108, 107–119 (2021).
  18. Jamila, G. S., Sajjad, S., Leghari, S.A.K., Mehboob, M., Flox, C. Enhanced electron transport by Fe₂O₃ on NCQDs–MgO nanostructure for solar photocatalysis and electrocatalytic water splitting. Appl Nanoscience.12, 1815–1827 (2022).
  19. Xu, Z., Wang, Y., Zhuang, J., Li, Y., & Jia, L. High temperature hydrothermal etching of g-C₃N₄ for synthesis of N-doped carbon quantum dots-supported CdS photocatalyst to enhance visible light driven hydrogen generation. Molecular Catalysis. 517, 111900.11900 (2022).
  20. Yousaf, Z., Sajjad, S., Leghari, S. A. K., Mehboob, M., Kanwal, A., & Uzair, B. Interfacial charge transfer via 2D-NiO and 2D-graphene nanosheets combination for significant visible photocatalysis. J Solid State Chem. 287, 121606 (2020)
  21. Zou, Y.J., Shi, J.W., Ma, D.K., Fan, Z.P., Niu, C.G. In situ synthesis of C-doped TiO₂@g-C₃N₄ core–shell hollow nanospheres with enhanced visible-light photocatalytic activity for H₂ evolution. Chem. Eng. J. 322, 435–444 (2017).
  22. Solayman, H. M., Abd Aziz, A., Yahya, N. Y., Leong, K. H., Sim, L. C., Hossain, M. K., . Zoh, K. D. CQDs embed g-C₃N₄ photocatalyst in dye removal and hydrogen evolution.n An insight review. J Water Process Eng. 57, 104645 (2024)
  23. Pan, J., You, M., Chi, C., Dong, Z., Wang, B., Zhu, M., Li, C.The two-dimension carbon quantum dots modified porous g-C₃N₄/TiO₂ nano heterojunctions for visible light hydrogen production enhancement. Int J Hydrogen Energy. 43, 6586–6593 (2018)
  24. Jindal, H., Kumar, D., Sillanpaa, M., & Nemiwal, M. Current progress in polymeric graphitic carbon nitride-based photocatalysts for dye degradation. Inorg Chem Commun.129, 108786 (2021)
  25. Liu, X., Yang, Z., Yang, Y., & Li, H. Construction of carbon quantum dots sensitized porous carbon nitride/titanium dioxide nanosheets for enhancing visible light photocatalytic degradation of tetracycline. Chem. Eng. J. 446, 108083 (2022)
  26. Abd Rani, U., Ng, L. Y., Ng, C. Y., & Mahmoudi, E. A review of carbon quantum dots and their applications in wastewater treatment. Adv. Colloid Interface Sci. 278, 102124 (2020)
  27. Wang, Y., Wang, X., & Antonietti, M. Polymeric graphitic carbon nitride as a heterogeneous organocatalyst: From photochemistry to multipurpose catalysis to sustainable chemistry. Angew Chem Int Ed. 51, 68–89 (2012)
  28. Zhang, Y., Mori, T., Ye, J., & Antonietti, M. Phosphorus-doped carbon nitride solid: Enhanced electrical conductivity and photocurrent generation. J Am Chem Soc. 132, 6294–6295 (2010)
  29. Cao, S., Low, J., Yu, J., & Jaroniec, M. Polymeric photocatalysts based on graphitic carbon nitride. Adv Mater. 27(13), 2150–2176 (2015)
  30. Shamaila, S., Sajjad, A. K. L., Chen, F., & Zhang, J. Synthesis and characterization of mesoporous TiO₂ with enhanced photocatalytic activity for the degradation of chlorophenol. Mater Res Bull. 45(45), 1375–1382 (2010)
  31. Liu, X., Yang, Y., Li, H., Yang, Z., & Fang, Y. Visible light degradation of tetracycline using oxygen-rich titanium dioxide nanosheets decorated by carbon quantum dots. Chem Eng J .408, 127259 (2021)
  32. Ong, W. J., Tan, L. L., Chai, S. P., & Yong, S. T. Heterojunction engineering of graphitic carbon nitride (g-C₃N₄) via Pt loading with improved daylight-induced photocatalytic reduction of carbon dioxide to methane. Dalton Trans. 44(3), 1249–1257 (2015)
  33. Jiang, J., Ou-yang, L., Zhu, L., Zheng, A., Zou, J., Yi, X., & Tang, H. Dependence of electronic structure of g-C₃N₄ on the layer number of its nanosheets: A study by Raman spectroscopy coupled with first-principles calculations. Carbon. 80, 213–221 (2014)
  34. Kumar, S., Nayak, D., Ansari, S., Bauri, J., & Choudhary, R. B. Investigation of structural, optical and thermal properties of TiO₂ reinforced g-C₃N₄ nanocomposite for emissive layer application. Mater Today Proc. 84, 557–562 (2023)
  35. Naveed, A. B., Javaid, A., Zia, A., Ishaq, M. T., Amin, M., Farooqi, Z. U. R., & Mahmood, A. TiO₂/g-C₃N₄ binary composite as an efficient photocatalyst for biodiesel production from Jatropha oil and dye degradation. ACS Omega, 8(2), 2173–2182 (2023)
  36. Sarp, G., Yildirim, E., Akyol, E. g-C₃N₄@TiO₂@Fe₃O₄ multifunctional nanomaterial for magnetic solid-phase extraction and photocatalytic degradation-based removal of trimethoprim and isoniazid. ACS Omega. 7(27), 23223–23233 (2022)
  37. Wang, J., Huang, J., Xie, H., & Qu, A. Synthesis of g-C₃N₄/TiO₂ with enhanced photocatalytic activity for H₂ evolution by a simple method. Int J Hydrogen Energy. 39, 6354–6363 (2014)
  38. Fagan, R., McCormack, D. E., Hinder, S. J., & Pillai, S. C. Photocatalytic properties of g-C₃N₄–TiO₂ heterojunctions under UV and visible light conditions. Materials. 9(4), 286 (2016)
  39. Liu, X., Yang, Y., Li, H., Yang, Z., & Fang, Y. Visible light degradation of tetracycline using oxygen-rich titanium dioxide nanosheets decorated by carbon quantum dots. Chem Eng J. 408, 127259 (2021)
  40. Deng, Y., Chen, M., Chen, G., Zou, W., Zhao, Y., Zhang, H., & Zhao, Q. Visible–Ultraviolet Upconversion Carbon Quantum Dots for Enhancement of the Photocatalytic Activity of Titanium Dioxide. ACS Omega. 6(6), 4247–4254(2021)
  41. Su, Y., Chen, P., Wang, F., Zhang, Q., Chen, T., Wang, Y., Liu, G. Decoration of TiO₂/g-C₃N₄ Z-scheme by carbon dots as a novel photocatalyst with improved visible-light photocatalytic performance for the degradation of enrofloxacin. RSC Adv. 7(54), 34096–34103 (2017)
  42. Liu, W., Li, Y., Liu, F., Jiang, W., Zhang, D., & Liang, J. Visible-light-driven photocatalytic degradation of diclofenac by carbon quantum dots modified porous g-C₃N₄: Mechanisms, degradation pathway and DFT calculation. Water Res.151, 8–19 (2019)
  43. Hu, K., Yao, M., Yang, Z., Xiao, G., Zhu, L., Zhang, H., ... & Liu, B. Pressure tuned photoluminescence and band gap in two-dimensional layered g-C₃N₄: the effect of interlayer interactions. Nanoscale. 12(23), 12300–12307 (2020)
  44. Noor, S., Haider, R. S., Noor, S., Sajjad, S., Leghari, S. A. K., Mehboob, M., & Long, M.. Role of conductive channels via CQDs on NiO/g-C₃N₄ Z-scheme composite as a bifunctional photocatalyst. Int J Hydrogen Energy. 47(86), 36517–36529 (2022)
  45. Li, G., Huang, J., Wang, N., Huang, J., Zheng, Y., Zhan, G., & Li, Q. Carbon quantum dots functionalized g-C₃N₄ nanosheets as enhanced visible-light photocatalysts for water splitting. Diam Relat Mater.116, 108242 (2021)
  46. Ren, B., Wang, T., Qu, G., Deng, F., Liang, D., Yang, W., & Liu, M. In situ synthesis of g-C₃N₄/TiO₂ heterojunction nanocomposites as a highly active photocatalyst for the degradation of Orange II under visible light irradiation. Environ Sci Pollut Res. 25(19), 19122–19133 (2018)
  47. Wang, W., Fang, J., Shao, S., Lai, M., & Lu, C. Compact and uniform TiO₂@g-C₃N₄ core-shell quantum heterojunction for photocatalytic degradation of tetracycline antibiotics. Appl Catal B Environ. 217, 57–64 (2017)
  48. Alqahtani, F. O. Advancing photocatalytic degradation under visible light with TiO2/g-C3N4 nanohybrid mechanistic insights. Journal of Saudi Chemical Society. 28(5), 1234–1245 (2024)
  49. Hoa, D. T. N., Tu, N. T. T., Thinh, H. Q. A., Van Thanh Son, L., Son, L. V. T., Quyen, N. D. V., Khieu, D.Q.TiO2/g‐C3N4 Visible‐Light‐Driven Photocatalyst for Methylene Blue Decomposition. Journal of Nanomaterials. 2023(1), 9967890(2023).
  50. Liu, W., Li, Y., Liu, F., Jiang, W., Zhang, D., & Liang, J. Visible-light-driven photocatalytic degradation of diclofenac by carbon quantum dots modified porous g-C₃N₄: mechanisms, degradation pathway and DFT calculation. Water Res. 151, 8–19 (2019)
  51. Tian, M., Hu, C., Yu, J., & Chen, L. Carbon quantum dots (CQDs) mediated Z-scheme g–C3N4–CQDs/BiVO4 heterojunction with enhanced visible light photocatalytic degradation of Paraben. Chemosphere. 308, 138248 (2023)
  52. Xu, Y., Hou, W., Huang, K., Guo, H., Wang, Z., Lian, C., ... & Wang, L. Engineering built-in electric field microenvironment of CQDs/g-C₃N₄ heterojunction for efficient photocatalytic CO₂ reduction. Adv. Sci. (Weinh.) 11(28), 2403607 (2024)
  53. Jin, T., Liu, C., Chen, F., Qian, J., Qiu, Y., Meng, X., Chen, Z. Synthesis of g-C₃N₄/CQDs composite and its photocatalytic degradation property for Rhodamine B. Carbon Lett. 32, 1451–1462 (2022)
  54. Vidyasagar, D., Ghugal, S. G., Kulkarni, A., Mishra, P., & Shende, A. G. Silver/Silver(II) oxide (Ag/AgO) loaded graphitic carbon nitride microspheres: an effective visible light active photocatalyst for degradation of acidic dyes and bacterial inactivation. Appl. Catal. B Environ. 221, 339–348 (2018)
  55. Mohini, R., & Lakshminarasimhan, N. Coupled semiconductor nanocomposite g-C₃N₄/TiO₂ with enhanced visible light photocatalytic activity. Mater. Res. Bull. 76, 370–375 (2016)
  56. Lu, Z., Zeng, L., Song, W., Qin, Z., Zeng, D., & Xie, C. In situ synthesis of C-TiO₂/g-C₃N₄ heterojunction nanocomposite as highly visible light active photocatalyst originated from effective interfacial charge transfer. Appl. Catal. B Environ. 202, 489–499 (2017)
  57. Zhang, J. J., Fang, S. S., Mei, J. Y., Zheng, G. P., Zheng, X. C., & Guan, X. X. High efficiency removal of rhodamine B dye in water using g-C₃N₄ and TiO₂ cohybridized 3D graphene aerogel composites. Sep. Purif. Technol. 194, 96–103 (2018)
  58. Das, S., Mahalingam, H. Dye degradation studies using immobilized pristine and waste polystyrene-TiO₂/rGO/g-C₃N₄ nanocomposite photocatalytic film in a novel airlift reactor under visible light irradiation. Sci. Total Environ. 690, 370–384 (2019)
  59. ] Feng, S., Chen, T., Liu, Z., Shi, J., Yue, X., & Li, Y. Z-scheme CdS/CQDs/g-C₃N₄ composites with visible-near-infrared light response for efficient photocatalytic organic pollutant degradation. Sci. Total Environ. 704, 135404 (2020)
  60. Hu, L., Yan, J., Wang, C., Chai, B., & Li, J. Direct electrospinning method for the construction of Z-scheme TiO₂/g-C₃N₄/RGO ternary heterojunction photocatalysts with remarkably ameliorated photocatalytic performance. Chin. J. Catal. 40(3), 458–469 (2019)
  61. Liu, R., Bie, Y., Qiao, Y., Liu, T., & Song, Y. Design of g-C₃N₄/TiO₂ nanotubes heterojunction for enhanced organic pollutants degradation in wastewater. Mater. Lett. 251, 126–130 (2019)
  62. Ji, H., Du, P., Zhao, D., Li, S., Sun, F., Duin, E. C., & Liu, W. 2D/1D graphitic carbon nitride/titanate nanotubes heterostructure for efficient photocatalysis of sulfamethazine under solar light: Catalytic “hot spots” at the rutile–anatase–titanate interfaces. Appl. Catal. B Environ. 263, 118357 (2020)
  63. Gündoğmuş, P., Park, J., & Öztürk, A. Preparation and photocatalytic activity of g-C₃N₄/TiO₂ heterojunctions under solar light illumination. Ceram. Int. 46(13), 21431–21438 (2020)
  64. Khan, A., Jonathan, R., Rehman, S. U., Shoaib, M., Cao, F., Ali, S., Jian, X. Ultra-fine carbon decorated TiO₂/C/g-C₃N₄ hybrid for strong physical adsorption and efficient photodegradation of pollutants. Arab. J. Chem. 16(1), 106034 (2025)
  65. Shoaib, M., Naz, M. Y., Shukrullah, S., Munir, M. A., Irfan, M., Rahman, S., & Ghanim, A. A. J. Dual S-scheme heterojunction CdS/TiO₂/g-C₃N₄ photocatalyst for hydrogen production and dye degradation applications. ACS Omega. 8(45), 43139–43150 (2023)
  66. Iram, F., Mallah, A. M., Safdar, M., Khitouni, M., Hammami, B., Alsehaibani, H. A. H., Alkhaibari, I. S. Fabrication and OER/HER electrochemical activity of Sm, Al assisted g-C3N4 nanocomposite for alkaline water splitting. Journal of Alloys and Compounds.1014, 178603(2025)
  67. Zhang, L., Yang, X., Yin, Z., Sun, L. A review on carbon quantum dots: Synthesis, photoluminescence mechanisms and applications. Luminescence. 37(10), 1612-1638 (2022)
  68. Noreen, H., Farooq, A., Naz, S., Amjed, N., Ahmad, A., Aftab, A.,Muzammal, S. From lab to environment: a critical eye approach toward morphological synthesis of graphitic carbon nitride for environmental restoration. Journal of the Iranian Chemical Society. 1-24 (2025)
  69. Liu, C., Wang, J., Xu, H., Li, Y., Zhang, H. Photo-Fenton degradation of tetracycline over Z-scheme Fe-g-C₃N₄/Bi₂WO₆ heterojunctions: mechanism insight, degradation pathways and DFT calculation. Appl. Catal. B Environ. 310, 121326–121340 (2022)
  70. Pandey, A., Alam, U., Gupta, A., Shim, J. J., Verma, N. S-scheme heterojunction-mediated hydrogen production over the graphitic carbon nitride-anchored nickel stannate perovskite. Fuel. 355, 129538 (2024)
  71. ] Ashok, K., Rosaiah, P., Radhalayam, D., Al-Zahrani, F. A. M.,Suneetha, M. Enhancing photocatalytic efficiency and hydrogen production through oxygen-defective g-C3N4/Fe2O3 composites. Diamond and Related Materials.112851 (2025)
  72. Bilal, A. S. S., Bilal, U., Abbas, T., Roopashree, R., Khudoynazarov, E., Yaxshimuratov, M.,Noman, H. M. Enhanced solar-driven hydrogen evolution via C3N4/NiO/ZnO ternary heterojunction nanocomposite with efficient charge separation. Next Energy. 9, 100417 (2025)
  73. Iram, F., Mallah, A. M., Safdar, M., Khitouni, M., Hammami, B., Alsehaibani, H. A. H., Alkhaibari, I. S. Fabrication and OER/HER electrochemical activity of Sm, Al assisted g-C3N4 nanocomposite for alkaline water splitting. Journal of Alloys and Compounds.1014, 178603 (2025)
  74. Backes, C. W., Reis, F. B., Strapasson, G. B., Assis, M., Longo, E., Weibel, D. E. (2025). Green Synthesis of carbon quantum dots for enhancing photocatalytic activity: Hydrogen/oxygen evolution and dye photodegradation. Catalysis Today. 443, 114996 (2025)