Malays. J. Anal. Sci. Volume 30 Number 3 (2026): 1740

Review Article

Mapping the photocatalysis landscape through bibliometric analysis: Ten years of global research trends and emerging fronts

Nur Khaliesa Zulkarnaen¹, Suzaliza Mustafar¹, Hafizul Fahri Hanafi ², Ma. Leah Borines³, and Etty Nurlia Kusumawati^4*

¹ Department of Chemistry, Faculty of Science and Mathematics, Universiti Pendidikan Sultan Idris, 35900 Tanjong Malim, Perak, Malaysia

² Faculty of Computing and Meta-Technology, Universiti Pendidikan Sultan Idris, 35900 Tanjong Malim, Perak, Malaysia

³ Department of Chemistry, University of Connecticut, 55 North Eagleville Road, Unit 3060, Storrs, Connecticut, U.S.A.

⁴ Chemistry Course, Faculty of Science and Engineering, Iwate University, 4-3-5, Morioka, 020-8551, Japan

^*Corresponding author: etty01@iwate-uc.ac.jp

Received: 6 October 2025; Revised: 20 January 2026; Accepted: 23 February 2026; Published: 30 June 2026

Abstract

Photocatalysis has emerged as a key research domain for sustainable energy conversion and environmental remediation; however, its rapid expansion necessitates a systematic synthesis of the literature. This study presents a bibliometric analysis of photocatalysis research based on 2,342 Scopus-indexed publications published between 2015 and 2025. Following OpenRefine-assisted data cleaning, the dataset was analysed using VOSviewer with fractional counting, association strength normalisation, and a minimum keyword occurrence threshold of five. The indicators covered annual publication output, citation performance, and author and source impact. The results revealed a pronounced growth trajectory after 2019, with publication output peaking in 2024 (n = 376; 16.05%) and remaining high in 2025 (n = 334; 14.26%), indicating sustained research momentum. Keyword co-occurrence mapping identified three dominant thematic clusters: (i) solar fuels and energy conversion (e.g. hydrogen evolution, g-C₃N₄, Z-scheme systems), (ii) environmental remediation and water treatment (e.g. photodegradation, wastewater treatment), and (iii) material design and characterisation (e.g. TiO₂, nanocomposites, spectroscopy). Citation patterns show that foundational review articles anchor the knowledge base, whereas recent high-impact studies signal a shift toward scalable solar-hydrogen technologies. Overall, the findings portray photocatalysis as a maturing interdisciplinary field transitioning from mechanistic studies to application-driven research.

Keywords: bibliometric, energy conversion, photocatalysis, scopus, VOSviewer

References

1. Kumar, A.S., Pabba, D.P., Reddy, N.R., and Joo, S.W. (2025). Emerging photocatalytic systems for environmental and energy applications: A comprehensive review of mechanisms, materials, and future directions, Journal of Alloys and Compounds, 180934.

2. Balu, S., Ganapathy, D., Arya, S., Atchudan, R., and Sundramoorthy, A. K. (2024). Advance photocatalytic materials based degradation of micropollutants and their use in hydrogen production–A review. RSC Advances, 14(20), 14392-14424.

3. Hassaan, M. A., El-Nemr, M. A., Elkatory, M. R., Ragab, S., Niculescu, V. C., and El Nemr, A. (2023). Principles of photocatalysts and their different applications: a review. Topics in Current Chemistry, 381(6), 31.

4. Antonopoulou, M., Kosma, C., Albanis, T., and Konstantinou, I. (2021). An overview of homogeneous and heterogeneous photocatalysis applications for the removal of pharmaceutical compounds from real or synthetic hospital wastewaters under lab or pilot scale. Science of the Total Environment, 765, 144163.

5. Cano, F. M., Molina, A. P., and Molenbroek, A. M. (2009). The use of synchrotron radiation in industrial heterogeneous catalysis. Synchrotron Radiation News, 22(1), 12-16.

6. Krishnakumar, S., Jeyabarathi, P., Abukhaled, M., and Rajendran, L. (2025). A semi-analytical solution of a nonlinear boundary value problem arises in porous catalysts. International Journal of Electrochemical Science, 20(3), 100953.

7. Al-Ahmed, Z. A., Alenazi, N. A., Almotairy, A. R. Z., Sallam, S., Alharbi, H., Ibarhiam, S. F., Alkhathami, N. D., and El-Metwaly, N. M. (2024). Remarkable recycling processes of conjugated polymers with titanium dioxide quantum dots as photocatalysts for photodegradation of hazardous industrial wastewater. Results in Engineering, 24, 103412.

8. He, X., Vikrant, K., Boukhvalov, D. W., and Kim, K. H. (2025). Synthesis, performance, and reaction mechanisms of titanium dioxide-silicon carbide as a step-scheme heterojunction photocatalyst against formaldehyde in air. Chemical Engineering Journal, 164114.

9. Huang Kong, E. D., Lai, C. W., Juan, J. C., Pang, Y. L., Khe, C. S., Badruddin, I. A., Gapsari, F., and Anam, K. (2025). Recent advances in titanium dioxide bio-derived carbon photocatalysts for organic pollutant degradation in wastewater. iScience, 28(5), 112368.

10. Ly, H. N., Parasuraman, V., Han, T. U., Park, J. B., Lee, W. R., and Kim, S. (2025). Enhanced removal of volatile organic compounds and bacterial disinfection using silver-integrated urchin-like porous titanium as a multifunctional photocatalyst. Journal of Cleaner Production 497, 145153.

11. Jiang, X., Wang, A., Peng, J., Song, X., and Wang, L. (2024). Preparing ruthenium complex-contained DaTp COFs via π–π interactions for visible-light-driven photocatalytic hydrogen peroxide production. Inorganic Chemistry 63(48), 23028-23035.

12. Lu, M., Zhang, S., Yang, M., Liu, Y., Liao, J., Huang, P., Zhang, M., Li, S., Su, Z., and Lan, Y. (2023). Dual photosensitizer coupled three‐dimensional metal‐covalent organic frameworks for efficient photocatalytic reactions. Angewandte Chemie International Edition, 62(31), e202307632.

13. Prekodravac, J. R., Nair, V., Giannakoudakis, D. A., Hsu, H.Y., and Colmenares, J. C. (2021). Homogeneous photocatalysts immobilized on polymeric supports: Environmental and chemical synthesis applications. In Materials Science in Photocatalysis, 575-588.

14. Yusuf, A. K. N. M., Mustafar, S., Borines, M. L., Kusumawati, E. N., and Hashim, N. (2021). Versatility of photosensitizers in dye-sensitized solar cells (DSSCs). Biointerface Research in Applied Chemistry, 12(6), 8543-8560.

15. Mustafar, S., Shoji, R., Toyoda, R., Maeda, H., Ogino, Y., Nishihara, H., and Sakamoto, R. (2025). One-dimensional bis (dipyrrinato) zinc (II)-linked porphyrinatozinc (II) polymer: synthesis, exfoliation into single wires, and photofunctionality. Bulletin of the Chemical Society of Japan, 98(6), 50.

16. Yusuf, A. K. N. M., Mustafar, S., Borines, M. L., Kusumawati, E. N., Juahir, Y., Ali, N. M., and Hashim, N. (2023). Synthesis and characterization of photoanode by immobilisation of pyridyl complexes on ito for photo-conversion system. Pakistan Journal of Analytical & Environmental Chemistry, 24(1), 86-93.

17. Mustafar, S., Wu, K.-H., Toyoda, R., Takada, K., Maeda, H., Miyachi, M., Sakamoto, R., and Nishihara, H. (2016). Electrochemical fabrication of one-dimensional porphyrinic wires on electrodes. Inorganic Chemistry Frontiers, 3(3), 370-375.

18. Mustafar, S., Yusuf, A. K. N. M., Borines, L. M., Kusumawati, E. N., Kamari, A., and Ali, N. M. (2023). Metal-organic framework nanosheets (MONs): A review on interfacial syntheses and applications of coordination nanosheets. Biointerface Research Applied Chemistry, 13(2).

19. Mak, C. H., Han, X., Du, M., Kai, J. J., Tsang, K. F., Jia, G., Cheng, K. C., Shen, H. H., and Hsu, H. Y. (2021). Heterogenization of homogeneous photocatalysts utilizing synthetic and natural support materials. Journal of Materials Chemistry A, 9(8), 4454–4504.

20. Shi, M., and Meng, X. (2023). Photothermal catalysis: From principles to applications. International Journal of Hydrogen Energy, 48(89), 34659-34676.

21. Winkler, W., and Williams, M. C. (2014). Fuel cells and flow batteries: A comparative process and design analysis. ECS Transactions, 56(1), 49-60.

22. El Mchaouri, M., Mallah, S., Abouhajjoub, D., Boumya, W., Elmoubarki, R., Essadki, A., Barka, N., and Elhalil, A. (2025). Engineering TiO2 photocatalysts for enhanced visible-light activity in wastewater treatment applications. Tetrahedron Green Chemistry, 6, 100084. 

23. Yadav, L., Laddha, H., Agarwal, M., and Gupta, R. (2024). A review on effective photocatalytic remediation of noxious pollutants utilizing biochar tailored graphitic carbon nitride. ACS Sustainable Resource Management, 1(8), 1855-1873.

24. Wang, S., Li, X., Dong, R., Xiong, W., Li, Y., and Zhu, Y. (2023). Integration of in-situ and ex-situ power-to-gas (Ptg) strategy for simultaneous bio-natural gas production and CO₂ emission reduction. Chemosphere, 344, 140370.

25. Arora, I., Chawla, H., Chandra, A., Sagadevan, S., and Garg, S. (2022). Advances in the strategies for enhancing the photocatalytic activity of TiO₂: Conversion from UV-light active to visible-light active photocatalyst. Inorganic Chemistry Communications, 143, 109700.

26. Elsayed, M. H., Abdellah, M., Alhakemy, A. Z., Mekhemer, I. M. A., Aboubakr, A. E. A., Chen, B. H., Sabbah, A., Lin, K. H., Chiu, W. S., Lin, S. J., Chu, C. Y., Lu, C. H., Yang, S. D., Mohamed, M. G., Kuo, S. W., Hung, C. H., Chen, L. C., Chen, K. H., and Chou, H. H. (2024). Overcoming small-bandgap charge recombination in visible and NIR-light-driven hydrogen evolution by engineering the polymer photocatalyst structure. Nature Communications, 15(1), 707.

27. Nasr, M., Eid, C., Habchi, R., Miele, P., and Bechelany, M. (2018). Recent progress on titanium dioxide nanomaterials for photocatalytic applications. ChemSusChem, 11(18), 3023-3047.

28. Fang, S., Zhang, W., Sun, K., Tong, T., Lim, A. I., Bao, J., Du, Z., Li, Y., and Hu, Y. H. (2022). Critical role of tetracycline’s self-promotion effects in its visible-light driven photocatalytic degradation over ZnO nanorods. Chemosphere, 309, 136691.

29. Kim, H., Jo, S., and Lee, T. S. (2021). Synthesis of chemically bound conjugated polymer on TiO₂ for a visible-light-driven photocatalyst: Changeable surface wettability. Materials & Design, 203, 109630.

30. Likodimos, V. (2018). Photonic crystal-assisted visible light activated TiO₂ photo catalysis. Applied Catalysis B: Environmental 230, 269-303.

31. Goodarzi, N., Ashrafi-Peyman, Z., Khani, E., and Moshfegh, A. Z. (2023). Recent progress on semiconductor heterogeneous photocatalysts in clean energy production and environmental remediation. Catalysts, 13(7), 1102.

32. Lin, M., Chen, H., Zhang, Z., and Wang, X. (2023). Engineering interface structures for heterojunction photocatalysts. Physical Chemistry Chemical Physics, 25(6), 4388-4407.

33. Yan, Y., Hao, L., Ren, Z., Shen, R., Liang, G., Zhang, P., Teng, Y., Xu, D., and Li, X. (2026). Design and modification strategies of covalent organic frameworks for photocatalytic hydrogen/hydrogen peroxide production. Journal of Materials Science & Technology, 249, 305-332.

34. Zhao, X., Zhang, X., Lei, M., Ma, X., Li, Y., and Jin, Z. (2026). Synergistic effect of morphology regulation of LaNiO₃ S-scheme heterojunction for enhanced photocatalytic hydrogen production. Journal of Materials Science & Technology, 245, 238-248.

35. Gomes, J., Lincho, J., Domingues, E., Quinta-Ferreira, R. M., and Martins, R. C. (2019). N–TiO₂ photocatalysts: A review of their characteristics and capacity for emerging contaminants removal. Water, 11(2), 373.

36. Chauke, N. M., Ngqalakwezi, A., and Raphulu, M. (2025). Transformative advancements in visible-light-activated titanium dioxide for industrial wastewater remediation. International Journal of Environmental Science and Technology, 22(9), 8521-8552.

37. Ma, H. Y., Zhao, L., Wang, D. B., Zhang, H., and Guo, L. H. (2018). Dynamic tracking of highly toxic intermediates in photocatalytic degradation of pentachlorophenol by continuous flow chemiluminescence. Environmental Science & Technology, 52(5), 2870-2877.

38. Jay, L., and Chirwa, E. M. N. (2018). Pathway analysis of phenol degradation by UV/TiO₂ photocatalysis utilising the c-13 isotopic labelling technique. Chemical Engineering Transactions, 70, 181–186.

39. Konstantinou, I. (2003). Photocatalytic transformation of pesticides in aqueous titanium dioxide suspensions using artificial and solar light: Intermediates and degradation pathways. Applied Catalysis B: Environmental, 42(4), 319-335.

40. Hua, X., Chen, H., Rong, C., Addison, F., Dong, D., Qu, J., Liang, D., Guo, Z., Zheng, N., and Liu, H. (2023). Visible-light-driven photocatalytic degradation of tetracycline hydrochloride by Z-scheme Ag₃PO₄/1T@2H-MoS₂ heterojunction: Degradation mechanism, toxicity assessment, and potential applications. Journal of Hazardous Materials, 448, 130951.

41. Mousavi, S. M., Mohtaram, M. S., Rasouli, K., Mohtaram, S., Rajabi, H., and Sabbaghi, S. (2025). Efficient visible-light-driven photocatalytic degradation of antibiotics in water by MXene-derived TiO₂-supported SiO₂/Ti₃C₂ composites: Optimisation, mechanism and toxicity evaluation. Environmental Pollution, 367, 125624

42. Naraginti, S., Li, Y., Wu, Y., Zhang, C., and Upreti, A. R. (2016). Mechanistic study of visible light driven photocatalytic degradation of EDC 17α-ethinyl estradiol and azo dye Acid Black-52: Phytotoxicity assessment of intermediates. RSC Advances, 6(90), 87246-87257. 

43. Xu, B., An, Z., Li, M., Zhang, B., and Guo, L. H. (2023). Photocatalytic degradation of tetrabromobisphenol A by Z-scheme WO₃/ZnIn₂S₄ heterojunction: Efficiency, mechanism and toxicity evaluation. Journal of Environmental Chemical Engineering, 11(6), 111522. 

44. Kelly, J., McDonnell, C., Skillen, N., Manesiotis, P., and Robertson, P. K. J. (2021). Enhanced photocatalytic degradation of 2-methyl-4-chlorophenoxyacetic acid (Mcpa) by the addition of H₂O₂. Chemosphere, 275, 130082.

45. Ahmed, M. A., and Mohamed, A. A. (2023). Recent progress in semiconductor/graphene photocatalysts: Synthesis, photocatalytic applications, and challenges. RSC Advances, 13(1), 421–439.

46. Sudrajat, H., and Nobatova, M. (2025). Heterojunction photocatalysts: Where are they headed? RSC Applied Interfaces, 2(3), 599-619.

47. Jian, A., Li, W., Wang, M., Jia, H., and Sang, S. (2021). Au‐TiO₂ ‐ZnO sandwich‐structured composite films with enhanced ultraviolet‐light photocatalytic activity. Micro & Nano Letters, 16(12), 601-609. 

48. Yu, Y., Qiao, Z., and Ding, C. (2024). Built‐in electric field boost photocatalytic degradation of pollutants in wastewater. The Chemical Record, 24(10), e202400106.

49. Huang, H., Chen, Y., and Shi, H. (2022). Boosting separation of charge carriers in 2d/0d biobr nanoflower sheets/bn quantum dots with the lorentz force via magnetic field. Energy & Fuels, 36(19), 11495-11502.

50. Li, H., Chen, R., Sun, L., Wang, Y., Liu, Q., Zhang, Q., Xiao, C., and Xie, Y. (2024). Hole polaron‐mediated suppression of electron–hole recombination triggers efficient photocatalytic nitrogen fixation. Advanced Materials, 36(44), 2408778.

51. Yadav, M., Yadav, A., Thorat, N., Varma, R., Pillai, S., Fernandes, R., Patel, R., and Patel, N. (2022). Strategically fabricated Ag loaded Fe-g-C3N4 nanosheet for photocatalytic removal of aqueous organic pollutant. Optical Materials, 125, 112043.

52. Sun, F., Xing, X., Zhang, C., Zhang, J., and Hong, H. (2024). Enhanced photocatalytic co₂ reduction performance via photothermal–magnetic synergistic effects for solar fuel production. ACS Sustainable Chemistry & Engineering, 12(8), 3298-3311.

53. Ojemaye, C. Y., Ojemaye, M. O., Okoh, A. I., and Okoh, O. O. (2023). Evaluation of the research trends on perfluorinated compounds using bibliometric analysis: Knowledge gap and future perspectives. Journal of Environmental Science and Health, Part A, 58(6), 570-595.

54. Semerjian, L., Okaiyeto, K., Ojemaye, M. O., Ekundayo, T. C., Igwaran, A., and Okoh, A. I. (2021). Global systematic mapping of road dust research from 1906 to 2020: Research gaps and future direction. Sustainability, 13(20), 11516.

55. Van Eck, N. J., and Waltman, L. (2010). Software survey: VOSviewer, a computer program for bibliometric mapping. Scientometrics, 84(2), 523-538.

56. Wen, J., Xie, J., Chen, X., and Li, X. (2017). A review on g-C₃N₄ -based photocatalysts. Applied Surface Science, 391, 72-123.

57. Xu, Q., Zhang, L., Yu, J., Wageh, S., Al-Ghamdi, A. A., and Jaroniec, M. (2018). Direct Z-scheme photocatalysts: Principles, synthesis, and applications. Materials Today, 21(10), 1042-1063.

58. Etacheri, V., Di Valentin, C., Schneider, J., Bahnemann, D., and Pillai, S. C. (2015). Visible-light activation of TiO₂ photocatalysts: Advances in theory and experiments. Journal of Photochemistry and Photobiology C: Photochemistry Reviews, 25, 1-29.

59. Cheng, L., Xiang, Q., Liao, Y., and Zhang, H. (2018). CdS-Based photocatalysts. Energy & Environmental Science, 11(6), 1362–1391.

60. Mishra, M., and Chun, D. M. (2015). α-Fe₂O₃ as a photocatalytic material: A review. Applied Catalysis A: General, 498, 126–141.

61. Wang, C. C., Li, J. R., Lv, X. L., Zhang, Y. Q., and Guo, G. (2014). Photocatalytic organic pollutants degradation in metal–organic frameworks. Energy Environmental Sciences, 7(9), 2831-2867.

62. Takata, T., Jiang, J., Sakata, Y., Nakabayashi, M., Shibata, N., Nandal, V., Seki, K., Hisatomi, T., and Domen, K. (2020). Photocatalytic water splitting with a quantum efficiency of almost unity. Nature, 581(7809), 411-414.

63. Nishiyama, H., Yamada, T., Nakabayashi, M., Maehara, Y., Yamaguchi, M., Kuromiya, Y., Nagatsuma, Y., Tokudome, H., Akiyama, S., Watanabe, T., Narushima, R., Okunaka, S., Shibata, N., Takata, T., Hisatomi, T., and Domen, K. (2021). Photocatalytic solar hydrogen production from water on a 100-m² scale. Nature, 598(7880), 304-307.

64. Zhang, J., Yu, J., Jaroniec, M., and Gong, J. R. (2012). Noble metal-free reduced graphene oxide-Zn _x Cd _1– x S nanocomposite with enhanced solar photocatalytic H₂ -production performance. Nano Letters, 12(9), 4584-4589.

65. Kumaravel, V., Mathew, S., Bartlett, J., and Pillai, S. C. (2019). Photocatalytic hydrogen production using metal doped TiO₂: A review of recent advances. Applied Catalysis B: Environmental, 244: 1021-1064.

66. Ma, D., Xue, Q., Liu, Y., Liang, F., Li, W., Liu, T., Zhuang, C., Zhao, Z., and Li, S. (2026). Manipulating interfacial charge redistribution in Mn_0.5Cd_0.5S/N-rich C₃N₅ S-scheme heterojunction for high-performance photocatalytic removal of emerging contaminants. Journal of Materials Science & Technology, 243, 265-274.

67. Wang, Q., Wang, G., Ren, H., Li, Z., Zhang, C., Chen, T., and Pang, H. (2025). Polyoxometalate-based materials for electrochemical energy storage and catalytic hydrogen production. Coordination Chemistry Reviews, 545, 217044.

68. Wang, Y., Liu, C., Liu, X., Han, J., Yang, L., Liao, X., and Yao, Y. (2025). Synthesis of (001) surface-oriented BiOBr for improved photocatalytic H₂O₂ production performance. Applied Surface Science, 710, 163963.

69. Zyoud, S., and Zyoud, A. H. (2025). Assessing progress on sustainable development goal 6 in the Arab world through performance and visualization analysis. Discover Sustainability, 6(1), 798.

70. Fujishima, A., Zhang, X., and Tryk, D. (2008). TiO₂ photocatalysis and related surface phenomena. Surface Science Reports, 63(12), 515-582.

71. Fujishima, A., and Honda, K. (1972). Electrochemical photolysis of water at a semiconductor electrode. Nature, 238(5358), 37–38.

72. Ennasraoui, B., Rhaya, M., Malekshah, R. E., Miyah, Y., Alahiane, S., Ouachtak, H., Jada, A., and Addi, A. A. (2026). A novel dual-Z-scheme g-C₃N₄/BiOCl/Ag₂WO₄ heterojunction engineered for sunlight-driven photocatalytic degradation of methylene blue and amoxicillin. Journal of Photochemistry and Photobiology A: Chemistry, 471, 116671.

73. Liu, X., Wang, T., Long, M., Zhan, H., and Wang, Y. (2026). Constructing bismuthene/Bi₄Ti₃O₁₂ heterojunctions via in-situ growth for enhanced visible-light photocatalytic activity. Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, 344, 126644.

74. Qiao, J., Jia, X., Zhang, L., Zhang, J., Song, Z., Wang, X., and Liu, Y. (2026). Phosphorus-doped C₃N₄ supported Fe-Ni-MOF heterojunction: A highly efficient photocatalyst for selective benzene hydroxylation. Journal of Photochemistry and Photobiology A: Chemistry, 470, 116607.

75. Wang, Z., and Bie, C. (2026). HOF/COF 2D/2D S-scheme heterojunction for photocatalytic H₂ production. Journal of Materials Science & Technology, 243, 206-208.

76. Vohra, M. I., Alasiri, A., Ateeq, M., Sakr, R. Y., Krzywiecki, M., Shehzad, K., Azizi, S., and Zada, A. (2025). Coordination between semiconductor defects and their role in charge separation and light absorption for exceptional solar light driven photocatalysis. Coordination Chemistry Reviews, 545, 217017.