Skip to main content
  • Original Paper: Sol-gel and hybrid materials for optical, photonic and optoelectronic applications
  • Published:

Creation of direct Z-scheme Al/Ga co-doping biphasic ZnO/g-C3N4 heterojunction for the sunlight-driven photocatalytic degradations of methylene blue


Al and Ga were co-doped into ZnO lattice (AGZ) by the sol–gel method. Herein, graphite carbon nitride (g-C3N4) was synthesized by using the thermal decomposition method, which was used to integrate with the obtained AGZ to create direct Z-scheme Al/Ga co-doping biphasic ZnO/g-C3N4 heterojunction by the simple single-phase dispersion method. The synthesized catalysts of composition, optical properties, topography structure and chemical state of element of the prepared AGZ/g-C3N4 composites were analyzed by XRD, FT-IR, UV, PL, TEM and XPS respectively. The results have shown that the combination of AGZ and g-C3N4 to form a direct Z-type heterojunction can effectively reduce the band gap of AGZ, thereby shifting the absorption edge to the visible light region. The PL spectroscopy study of the synthesized sample found that, compared with bare g-C3N4 or AGZ catalyst, AGZ/g-C3N4 significantly reduced the recombination of photogenerated electrons and holes, thereby ensuring that more reactive groups participate in the dye degradation process. The degradation experiment of methylene blue(MB) dye verifies that the AGZ/CN sample has excellent photocatalytic performance. Al/Ga co-doped ZnO/g-C3N4 catalyst showed the maximum photocatalytic MB degradation of 95.4% after 150 min in visible light illumination, while the degradation efficiency of ZnO and g-C3N4 are only 30.5% and 50.1%, respectively. It have observed that ·O2, ·OH and h+ radicals were the main active species that affect the photocatalytic degradation of dyes by radical trapping experiment. In addition, the heterojunction formed by AGZ and g-C3N4 inhibited the photocorrosion of ZnO, which was confirmed by these five consecutive dye degradation tests. At the same time, in order to determine the optimal compounding ratio, four groups of AGZ/CN with different ratios were prepared. It was found that AGZ/CN15 has the highest catalytic efficiency, and the degradation of MB reached 94% within 2.5 h. This work will open up a new path for the development of more effective photocatalysts for organic matter treatment.

Graphical abstract


  • The new idea of Al/Ga co-doping ZnO and graphite carbon nitride composite to improve nano-ZnO is realized.

  • For the composite materials, light absorption is strong, carrier concentration is high, recombination rate is low, and various optical properties are improved.

  • A Z-type heterojunction that can improve its photocatalytic performance is formed in the nano-ZnO.

  • The stability is extremely strong, and the photocatalytic activity hardly weakens after five cycles of catalytic reaction.

This is a preview of subscription content, access via your institution.

Fig. 1
Fig. 2
Fig. 3
Fig. 4
Fig. 5
Fig. 6
Fig. 7
Fig. 8
Fig. 9
Fig. 10
Fig. 11
Fig. 12


  1. Chen H, Wang X, Li J, Wang XK (2015) Cotton derived carbonaceous aerogels for the efficient removal of organic pollutants and heavy metal ions. J Mater Chem A 3(11):6073–6081

    CAS  Article  Google Scholar 

  2. Hansima MACK, Makehelwala M, Jinadasa KBSN, Wei Y, Nanayakkara KGN, Ajith CH, Weerasooriya R(2021) Fouling of ion exchange membranes used in the electrodialysis reversal advanced water treatment: a review. Chemosphere 263:127951

    CAS  Article  Google Scholar 

  3. Meidanchi A, Akhavan O (2014) Superparamagnetic zinc ferrite spinel–graphene nanostructures for fast wastewater purification. Carbon 69:230–238

    CAS  Article  Google Scholar 

  4. Fang X, Li J, Li X, Pan S, Zhang X, Sun X (2017) Internal pore decoration with polydopamine nanoparticle on polymeric ultrafiltration membrane for enhanced heavy metal removal. Chem Eng J 314:38–49

    CAS  Article  Google Scholar 

  5. Li ZJ, Zhang FH, Meng AL, Xie CC, Xing J (2015) ZnO/Ag micro/nanospheres with enhanced photocatalytic and antibacterial properties synthesized by a novel continuous synthesis method. RSC Adv 5:612–620

    CAS  Article  Google Scholar 

  6. Qiao X-Q, Zhang Z-W, Li Q-H, Hou D, Zhang Q, Zhang J, Li D-S, Feng P, Bu X(2018) In situ synthesis of n–n Bi2MoO6 & Bi2S3 heterojunctions for highly efficient photocatalytic removal of Cr(vi) J Mater Chem A 6(45):22580–22589

    CAS  Article  Google Scholar 

  7. Shi BY, Li GH, Wang DS, Feng CH, Tang HX (2007) Removal of direct dyes by coagulation: the performance of preformed polymeric aluminum species. Hazard Mater 143:567–574

    CAS  Article  Google Scholar 

  8. Gupta VK, Saleh TA (2013) Sorption of pollutants by porous carbon, carbon nanotubes and fullerene–an overview. Environ Sci Pollut Res 20:2828–2843

    CAS  Article  Google Scholar 

  9. Lee J, Ham S, Choi D, Jang DJ (2018) Facile fabrication of porous ZnS nanostructures with a controlled amount of S vacancies for enhanced photocatalytic performances. Nanoscale 10:14254–14263

    CAS  Article  Google Scholar 

  10. Samadi, M, Zirak, M, Naseri, A, Kheirabadi, M, Ebrahimi, M, Moshfegh A (2019) Design and tailoring of one-dimensional ZnO nanomaterials for photocatalytic degradation of organic dyes: a review. Res Chem Intermed 45:2197–2254

  11. Liu Y, Wei S, Gao W (2015) Ag/ZnO heterostructures and their photocatalytic activity under visible light: effect of reducing medium. J Hazard Mater 287(apr.28):59–68

    CAS  Article  Google Scholar 

  12. Sanakousar FM, Vidyasagar CC, Jim´enez-P´erez VM, Prakash K(2022) Recent progress on visible-light-driven metal and non-metal doped ZnO nanostructures for photocatalytic degradation of organic pollutants Mater Sci Semiconductor Process 140(15):106390

    CAS  Article  Google Scholar 

  13. Zirak M, Akhavan O, Moradlou O et al. (2014) Vertically aligned ZnO@CdS nanorod heterostructures for visible light photoinactivation of bacteria. J Alloy Compd 590:507–513

    CAS  Article  Google Scholar 

  14. Nourmohammadi A, Rahighi R, Akhavan O et al. (2014) Graphene oxide sheets involved in vertically aligned zinc oxide nanowires for visible light photoinactivation of bacteria. J Alloy Compd 612:380–385

    CAS  Article  Google Scholar 

  15. Akhavan O, Azimirad R, Safa S (2011) Functionalized carbon nanotubes in ZnO thin films for photoinactivation of bacteria. Mater Chem Phys 130(1-2):598–602

    CAS  Article  Google Scholar 

  16. Qiu R, Zhang D, Mo Y et al. (2008) Photocatalytic activity of polymer-modified ZnO under visible light irradiation. J Hazard Mater 156(1-3):80–85

    CAS  Article  Google Scholar 

  17. Kumar R, Anandan S, Hembram K et al. (2014) Efficient ZnO-based visible-light-driven photocatalyst for antibacterial applications. Acs Appl Mater Interfaces 6(15):13138–13148

    CAS  Article  Google Scholar 

  18. Pang X, Cui C, Su M, Wang Y, Wei Q, Tan W (2018) Construction of self-powered cytosensing device based on ZnO nanodisks@g-C3N4 quantum dots and application in the detection of CCRF-CEM cells. Nano Energy 46:101–109

    CAS  Article  Google Scholar 

  19. Liu J, Yan X-T, Qin X-S, Wu S-J, Zhao H, Yu W-B, Chen L-H, Li Y, Su B-L (2020) Light-assisted preparation of heterostructured g-C3N4/ZnO nanorods arrays for enhanced photocatalytic hydrogen performance. Catal Today 355:932–936

  20. Berlina AN, Zherdev AV, Dzantiev BB (2019) Progress in rapid optical assays for heavy metal ions based on the use of nanoparticles and receptor molecules. Microchim Acta 186:172

    Article  Google Scholar 

  21. Mahdavi Reza, Talesh SSA (2017) Sol-gel synthesis, structural and enhanced photocatalytic performance of Al doped ZnO nanoparticles. Adv Powder Technol 28(5):1418–1425

    CAS  Article  Google Scholar 

  22. Li X, Hu Z, Liu J, Li D, Zhang X, Chen J (2016) Ga doped ZnO photonic crystals with enhanced photocatalytic activity and its reaction mechanism. Appl Catal B Environ 195:29–38

    CAS  Article  Google Scholar 

  23. Liu J, Zhang W, Song D, Ma Q, Zhang L, Zhang H (2013) Investigation of aluminum–gallium co-doped zinc oxide targets for sputtering thin film and photovoltaic application. J Alloys Compd 575:174–182

  24. Ma H, Williams PL, Diamond SA (2013) Ecotoxicity of manufactured ZnO nanoparticles–a review. Environ Pollut 172:76–85

    CAS  Article  Google Scholar 

  25. Mamba G, Mishra AK (2016) Graphitic carbon nitride (g-C3N4) nanocomposites: a new and exciting generation of visible light driven photocatalysts for environmental pollution remediation. Appl Catal B Environ 198:347–377

    CAS  Article  Google Scholar 

  26. Ahmad I (2020) Comparative study of metal (Al, Mg, Ni, Cu and Ag) doped ZnO/g-C3N4 composites: efficient photocatalysts for the degradation of organic pollutants. Sep Purif Technol 251:117372

  27. Huang L, Xu H, Li Y, Li H, Cheng X, Xia J, Xu Y, Cai G (2013) Visible-light-induced WO3/g-C3N4 composites with enhanced photocatalytic activity. Dalton Trans 42:8606

  28. Li H, Xie M, Huang L, Xu H, Li Y, Huang S, Xu Y, Zhang Q (2015) Magnetically separable Fe2O3/g-C3N4 catalyst with enhanced photocatalytic activity. RSC Adv 5:95727–95735

  29. Lu M, Pei Z, Weng S, Feng W, Fang Z, Zheng Z, Huang M, Liu P (2014) Constructing atomic layer g-C3N4-CdS nanoheterojunctions with efficiently enhanced visible light photocatalytic activity. Phys Chem Chem Phys 16:21280–21288

    CAS  Article  Google Scholar 

  30. Tan L, Xu J, Zhang X, Hang Z, Jia Y, Wang S (2015) Synthesis of g-C3N4/CeO2 nanocomposites with improved catalytic activity on the thermal decomposition of ammonium perchlorate. Appl Surf Sci 356:447–453

  31. Wei W, Zhu Y, Wang J, Chen X, Yao W, Gao X, Zong R, Yang Z (2017) Core-shell g-C3N4@ZnO composites as photoanodes with double synergistic effects for enhanced visible-light photoelectrocatalytic activities. Appl Catal B Environ 217:169–180

    Article  Google Scholar 

  32. Zhou P, Yu J, Jaroniec M (2014) All-solid-state Z-scheme photocatalytic systems. Adv Mater 26(29):4920–4935

    CAS  Article  Google Scholar 

  33. Wang Y, Wang Q, Zhan X, Wang F, Safdar M, He J (2013) Visible light driven type II heterostructures and their enhanced photocatalysis properties: a review. Nanoscale 5(18):8326

    CAS  Article  Google Scholar 

  34. Ong WJ, Tan LL, Ng YH, Yong ST, Chai SP (2016) Graphitic carbon nitride (g-C3N4)-based photocatalysts for artificial photosynthesis and environmental remediation: are we a step closer to achieving sustainability?. Chem Rev 116(12):7159–7329

    CAS  Article  Google Scholar 

  35. Li S, Liu T, Zhang Y, Zeng W, Pan F, Peng X (2015) Hydrothermal synthesis of the sealed ZnO nanotube and its growth mechanism. Mater Lett 143:12–15

    CAS  Article  Google Scholar 

  36. Lin ZZ, Wang XC (2013) Nanostructure engineering and doping of conjugated carbon nitride semiconductors for hydrogen photosynthesis. Angew Chem Int Ed 52:1735–1738

    CAS  Article  Google Scholar 

  37. Chen Q, Hou H, Zhang D, Hu S, Min T, Liu B (2018) Enhanced visible-light driven photocatalytic activity of hybrid ZnO/gC3N4 by high performance ball milling. J Photochem Photobiol A Chem 350:1–9

  38. Prabhu S, Pudukudy M, Sohila S, Harish S, Navaneethan M, Navaneethan D, Ramesh R, Hayakawa Y (2018) Synthesis, structural and optical properties of ZnO spindle/reduced graphene oxide composites with enhanced photocatalytic activity under visible light irradiation. Opt Mater 79:186–195

    CAS  Article  Google Scholar 

  39. Akhundi A, Habibi-Yangjeh A (2015) Ternary g-C3N4/ZnO/AgCl nanocomposites: synergistic collaboration on visible-light-driven activity in photodegradation of an organic pollutant. Appl Surf Sci 358:261–269

    CAS  Article  Google Scholar 

  40. Zhou D, Qiu Q (2019) Study on the effect of Co doping concentration on optical properties of g-C3N4. Chemical Phys Lett 728:70–73

  41. Sun JX, Yuan YP, Qiu LG, Jiang X, Xie AJ, Shen YH, Zhu JF (2012) Fabrication of cmposite photocatalyst g-C3N4-ZnO and enhancement of photocatalytic activity under visible light. Dalton Trans 41:6756–6763.

  42. Fageria P, Nazir R, Gangopadhyay S, Barshilia HC, Pande S (2015) Graphitic-carbon nitride support for the synthesis of shape-dependent ZnO and their application in visible light photocatalysts. RSC Adv 5:80397–80409

  43. Lu YC, Lin YH, Wang DJ, Wang LL, Xie TF, Jiang TF (2011) A high performance cobalt-doped ZnO visible light photocatalyst and its photogenerated charge transfer properties. Nano Res 4:1144–1152

    CAS  Article  Google Scholar 

  44. Prabhu S, Pudukudy M, Harish S, Navaneethan M, Ramesh R (2020) Facile construction of djembe-like ZnO and its composite with g-C3N4 as a visible-light-driven heterojunction photocatalyst for the degradation of organic dyes. Mater Sci Semiconductor Process 106:104754

    CAS  Article  Google Scholar 

  45. Liang, L, Xi, L, Yizhi, L (2018) Facile synthesis of few-layer g-C3N4/ZnO composite photocatalyst for enhancing visible light photocatalytic performance of pollutants removal. Colloids Surfaces A 537 516–523

  46. Zhanga, Xingmiao, Liu, Yousong, Wei, & Lv. Enhancement photocatalytic activity of the graphite-like g-C3N4 coated hollow pencil-like ZnO. J. Colloid Interface Sci 450:381–387

  47. Zhang ZW, Li QH, Qiao XQ, Hou DF, Li DS (2019) One-pot hydrothermal synthesis of willow branch-shaped MoS2/CdS heterojunctions for photocatalytic H2 production under visible light irradiation. Chin J Catal 40(3):371–379

    CAS  Article  Google Scholar 

  48. Wang C, Xu D, Xiao X, Zhang Y, Zhang D (2007) Effects of oxygen pressure on the structure and photoluminescence of ZnO thin films. Mater Sci 42:9795–9800

    CAS  Article  Google Scholar 

  49. Qamar MA, Shahid S, Javed M, Iqbal S, & Akbar MB (2020) Highly efficient g-C3N4/Cr-ZnO nanocomposites with superior photocatalytic and antibacterial activity. J Photochem Photobiol A Chem 401:112776

  50. Li Q, Qiao XQ, Jia Y, Hou DF, Li DS (2019) Noble-metal-free amorphous CoMoS_x modified CdS core-shell nanowires for dramatically enhanced photocatalytic hydrogen evolution under visible light irradiation. Appl Surf Sci 498:143863.1–143863.11

    Google Scholar 

  51. Qiao XQ, Zhang ZW, Hou DF, Li D, Liu Y, Lan YQ, Jian Z, Feng P, Bu X (2018) Tunable MoS2/SnO2 P-N heterojunctions for efficient trimethylamine gas sensor and 4-nitrophenol reduction catalyst. ACS Sustain Chem Eng 6:12375–12384

    CAS  Article  Google Scholar 

  52. Akhavan O, Abdolahad M, Esfandiar A, Mohatashamifar M (2010) Photodegradation of graphene oxide sheets by TiO2 nanoparticles after a photocatalytic reduction. Phys Chem C 114:12955–12959

    CAS  Article  Google Scholar 

  53. Akhavan O (2010) Graphene nanomesh by ZnO nanorod photocatalysts. ACS Nano 4:4174–4180

  54. Ranjith KS, Kumar RTR(2017) Regeneration of an efficient, solar active hierarchical ZnO flower photocatalyst for repeatable usage: controlled desorption of poisoned species from active catalytic sites RSC Adv 7:4983–4992

    CAS  Article  Google Scholar 

  55. Wang Y, Shi R, Lin J, Zhu Y (2011) Enhancement of photocurrent and photocatalytic activity of ZnO hybridized with graphite-like C3N4. Energy Environ Sci 4:2922–2929

  56. Low J, Jiang C, Cheng B, Wageh S, Al-Ghamdi AA, Yu J (2017) A review of direct Z-scheme photocatalysts. Small Methods 1:1700080

  57. Wang J, Xia Y, Zhao H, Wang G, Xiang L, Xu J, Komarneni S (2017) Oxygen defects-mediated Z-scheme charge separation in g-C3N4/ZnO photocatalysts for enhanced visible-light degradation of 4-chlorophenol and hydrogen evolution. Appl Catal B Environ 206:406–416

    CAS  Article  Google Scholar 

Download references


This work was supported by the National Natural Science Foundation of China (No. 51502155), the Chinese Ministry of Education (111 Project D20015) and Natural Science Foundation of Yichang City (A20-3-006).

Author information

Authors and Affiliations


Corresponding author

Correspondence to Yihua Sun.

Ethics declarations

Conflict of interest

The authors declare no competing interests.

Additional information

Publisher’s note Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

Supplementary Information

Rights and permissions

Reprints and Permissions

About this article

Verify currency and authenticity via CrossMark

Cite this article

Luo, Q., Sun, Y., Lv, X. et al. Creation of direct Z-scheme Al/Ga co-doping biphasic ZnO/g-C3N4 heterojunction for the sunlight-driven photocatalytic degradations of methylene blue. J Sol-Gel Sci Technol 103, 876–889 (2022).

Download citation

  • Received:

  • Accepted:

  • Published:

  • Issue Date:

  • DOI:


  • Al/Ga co-doping
  • Graphitic carbon nitride
  • Direct Z-scheme heterojunction
  • Photocatalytic activity
  • Methylene blue