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doi: https://doi.org/10.53941/see.2024.100009
Liu, H., Shao, Y., Dou, S., & Pan, C. Enhanced Photo-Fenton Degradation of Antibiotics through Internal Electric Field Formation at the Interface of Mixed-Phase FeS₂. Science for Energy and Environment. 2024. doi: https://doi.org/10.53941/see.2024.100009
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Article

Enhanced Photo-Fenton Degradation of Antibiotics through Internal Electric Field Formation at the Interface of Mixed-Phase FeS₂

Hongyan Liu 1,2, Yunhang Shao 1,2, Shuai Dou 1,2 and Chengsi Pan 1,2,*

1 Key Laboratory of Synthetic and Biological Colloids, Ministry of Education, School of Chemical and Material Engineering, Jiangnan University, Wuxi 214122, China

2 International Joint Research Center for Photoresponsive Molecules and Materials, Jiangnan University, Wuxi 214122, China

* Correspondence: cspan@jiangnan.edu.cn

Received: 9 September 2024; Revised: 9 October 2024; Accepted: 13 November 2024; Published: 15 November 2024

 

Abstract: Iron sulfide (FeS₂) is a rich mineral resource widely used as an efficient Fenton and photo-Fenton reagent due to its non-toxicity and low synthesis cost. However, the mechanism underlying its photo-Fenton degradation activity related to the two crystal phases—pyrite (P-FeS₂) and marcasite (M-FeS₂)—is still not well understood. In this study, P-FeS₂, M-FeS₂, and their mixed phase (P/M-FeS₂) were prepared through hydrothermal reactions. The results showed that P/M-FeS₂ exhibited the highest photo-Fenton degradation activity, achieving a removal rate of approximately 99% for 50 ppm of ciprofloxacin (CIP) within 3 minutes, outperforming other photo-Fenton catalysts in pollutant degradation. The study revealed that an internal electric field (IEF) is generated at the interface of M-FeS₂ and P-FeS₂ due to their differing work functions. This IEF accelerates the regeneration of the active sites (Fe²⁺ in S₂²⁻-P-FeS₂ and M-FeS₂) required for the Fenton reaction, thereby explaining the superior activity of the P/M-FeS₂ mixed phase. This study introduces the IEF theory for the first time to explain the mechanism of mixed-phase catalysts in the photo-Fenton reaction. The formation of IEF can enhance the regeneration of the active sites involved in the Fenton reaction, thereby improving both reaction activity and stability. This work highlights the significance of regulating crystal phases in the degradation of pollutants during heterogeneous Fenton reactions and offers insights for developing highly efficient Fenton catalysts.

Keywords:

Fenton FeS₂ crystal phases antibiotics internal electric field

References

  1. Lin, Y.; Wang, Y.; Shi, C.; Zhang, D.; Liu, G.; Chen, L.; Yuan, B.; Hou, A.; Zou, D.; Liu, X.; et al. Degradation of ciprofloxacin by a constitutive g-C3N4/BiOCl heterojunction under a persulfate system. RSC Adv. 2023, 13, 4361–4375. https://doi.org/10.1039/d2ra06500b.
  2. Ferreira, V.R.A.; Amorim, C.L.; Cravo, S.M.; Tiritan, M.E.; Castro, P.M.L.; Afonso, C.M.M. Fluoroquinolones biosorption onto microbial biomass: Activated sludge and aerobic granular sludge. Int. Biodeterior. Biodegrad. 2016, 110, 53–60. https://doi.org/10.1016/j.ibiod.2016.02.014.
  3. El-Sheikh, S.M.; Hakki, A.; Ismail, A.A.; Badawy, W.A.; Bahnemann, D.W. Highly active non-metals doped mixed-phase TiO2 for photocatalytic oxidation of ibuprofen under visible light. J. Photochem. Photobiol. A Chem. 2017, 346, 530–540. https://doi.org/10.1016/j.jphotochem.2017.07.004.
  4. Khedr, T.M.; El-Sheikh, S.M.; Abdeldayem, H.M.; Ismail, A.A.; Kowalska, E.; Bahnemann, D.W. A comparative study of microcystin-LR degradation by UV-A, solar and visible light irradiation using bare and C/N/S-modified titania. Catalysts 2019, 9, 877. https://doi.org/10.3390/catal9110877.
  5. Yi, K.; Wang, D.; Yang, Q.; Li, X.; Chen, H.; Sun, J.; An, H.; Wang, L.; Deng, Y.; Liu, J.; Zeng, G. Effect of ciprofloxacin on biological nitrogen and phosphorus removal from wastewater. Sci. Total Environ. 2017, 605, 368–375. https://doi.org/10.1016/j.scitotenv.2017.06.215.
  6. Zheng, J.; Zhang, P.; Li, X.; Ge, L.; Niu, J. Insight into typical photo-assisted AOPs for the degradation of antibiotic micropollutants: Mechanisms and research gaps. Chemosphere 2023, 343, 140211–140211. https://doi.org/10.1016/j.chemosphere.2023.140211.
  7. Khedr, T.M.; El-Sheikh, S.M.; Kowalska, E.; Abdeldayem, H.M. The synergistic effect of anatase and brookite for photocatalytic generation of hydrogen and diclofenac degradation. J. Environ. Chem. Eng. 2021, 9, 106566. https://doi.org/10.1016/j.jece.2021.106566.
  8. Xiong, J.-Q.; Kurade, M.B.; Kim, J.R.; Roh, H.-S.; Jeon, B.-H. Ciprofloxacin toxicity and its co-metabolic removal by a freshwater microalga Chlamydomonas mexican. J. Hazard. Mater. 2017, 323, 212–219. https://doi.org/10.1016/j.jhazmat.2016.04.073.
  9. Wang, Y.; Chen, J.; Gao, J.; Meng, H.; Chai, S.; Jian, Y.; Shi, L.; Wang, Y.; He, C. Selective electrochemical H2O2 generation on the graphene aerogel for efficient electro-Fenton degradation of ciprofloxacin. Sep. Purif. Technol. 2021, 272, 118884. https://doi.org/10.1016/j.seppur.2021.118884.
  10. Walkowiak, A.; Wolski, L.; Ziolek, M. The influence of ferrocene anchoring method on the reactivity and stability of SBA-15-based catalysts in the degradation of ciprofloxacin via photo-Fenton process. RSC Adv. 2023, 13, 8360–8373. https://doi.org/10.1039/d3ra00188a.
  11. Nie, X.; Li, G.; Li, S.; Luo, Y.; Luo, W.; Wan, Q.; An, T. Highly efficient adsorption and catalytic degradation of ciprofloxacin by a novel heterogeneous Fenton catalyst of hexapod-like pyrite nanosheets mineral clusters. Appl. Catal. B-Environ. 2022, 300, 120734. https://doi.org/10.1016/j.apcatb.2021.120734.
  12. Yu, Y.; Sun, Y.; Zhou, Y.; Xu, A.; Xu, Y.; Huang, F.; Zhang, Y. The behavior of surface acidity on photo-Fenton degradation of ciprofloxacin over sludge derived carbon: Performance and mechanism. J. Colloid Interface Sci. 2021, 597, 84–93. https://doi.org/10.1016/j.jcis.2021.03.156.
  13. Bossmann, S.H.; Oliveros, E.; Göb, S.; Siegwart, S.; Dahlen, E.P.; Payawan, L.; Straub, M.; Wörner, M.; Braun, A.M. New evidence against hydroxyl radicals as reactive intermediates in the thermal and photochemically enhanced fenton reactions. J. Phys. Chem. A 1998, 102, 5542–5550. https://doi.org/10.1021/jp980129j.
  14. Hakimi, M.; Alikhani, M.J.J. o. I.; Polymers, O.; Materials, Characterization of α-Fe2O3 nanoparticles prepared from a new [Fe (Ofloxacin) 2Cl2] precursor: A heterogeneous photocatalyst for removal of methylene Blue and ciprofloxacin in water. J. Inorg. Organomet. Polym. Mater. 2020, 30, 504–512.
  15. Qiu, B.; Li, Q.; Shen, B.; Xing, M.; Zhang, J. Stöber-like method to synthesize ultradispersed Fe3O4 nanoparticles on graphene with excellent Photo-Fenton reaction and high-performance lithium storage. Appl. Catal. B: Environ. 2016, 183, 216–223. https://doi.org/10.1016/j.apcatb.2015.10.053.
  16. Wang, X.; Wang, J.; Cui, Z.; Wang, S.; Cao, M.J.R. Facet effect of α-Fe2 O3 crystals on photocatalytic performance in the photo-Fenton reaction. RSC Adv. 2014, 4, 34387–34394. https://doi.org/10.1039/C4RA03866E.
  17. Holmes, P.R.; Crundwell, F.K. The kinetics of the oxidation of pyrite by ferric ions and dissolved oxygen: An electrochemical study. Geochim. Cosmochim. Acta 2000, 64, 263–274. https://doi.org/10.1016/s0016-7037(99)00296-3.
  18. Liu, W.; Wang, Y.; Ai, Z.; Zhang, L. Hydrothermal Synthesis of FeS2 as a High-Efficiency Fenton Reagent to Degrade Alachlor via Superoxide-Mediated Fe(II)/Fe(III) Cycle. ACS Appl. Mater. Interfaces 2015, 7, 28534–28544. https://doi.org/10.1021/acsami.5b09919.
  19. Zeng, L.; Gong, J.; Dan, J.; Li, S.; Zhang, J.; Pu, W.; Yang, C. Novel visible light enhanced Pyrite-Fenton system toward ultrarapid oxidation of p-nitrophenol: Catalytic activity, characterization and mechanism. Chemosphere 2019, 228, 232–240. https://doi.org/10.1016/j.chemosphere.2019.04.103.
  20. Zhang, F.; Liu, J.; Yue, H.; Cheng, G.; Xue, X. Enhanced photo-Fenton catalytic activity by spherical FeS2 nanoparticles and photoelectric property of hybrid FeS2/rGO. Vacuum 2021, 192, 110433. https://doi.org/10.1016/j.vacuum.2021.110433.
  21. Schmokel, M.S.; Bjerg, L.; Cenedese, S.; Jorgensen, M.R.V.; Chen, Y.-S.; Overgaard, J.; Iversen, B.B. Atomic properties and chemical bonding in the pyrite and marcasite polymorphs of FeS2: A combined experimental and theoretical electron density study. Chem. Sci. 2014, 5, 1408–1421. https://doi.org/10.1039/c3sc52977k.
  22. Huang, X.; Wei, J.; Jiang, X.; Nan, Z. FeS2/SiO2 mesoporous hollow spheres formation and catalytic properties in the Fenton reaction. Mater. Lett. 2020, 277, 128408. https://doi.org/10.1016/j.matlet.2020.128408.
  23. Diao, Z.-H.; Liu, J.-J.; Hu, Y.-X.; Kong, L.-J.; Jiang, D.; Xu, X.; Technology, P. Comparative study of Rhodamine B degradation by the systems pyrite/H2O2 and pyrite/persulfate: Reactivity, stability, products and mechanism. Sep. Purif. Technol. 2017, 184, 374–383. https://doi.org/10.1016/j.seppur.2017.05.016.
  24. Lin, Y.; Li, J.; Chen, S.; Zhou, H.; Shu, Y.; Tang, L.; Long, Q.; Zhang, P.; Huang, Y.; Technology, P. In situ construction of pyrite-marcasite-magnetite composite via FeS2 phase transformation and oxidation for the synergistic degradation of methyl orange and Cr (VI). Sep. Purif. Technol. 2023, 308, 122764. https://doi.org/10.1016/j.seppur.2022.122764.
  25. Cui, P.; Hu, Y.; Zheng, M.; Wei, C. Enhancement of visible-light photocatalytic activities of BiVO4 coupled with g-C3N4 prepared using different precursors. Environ. Sci. Pollut. Res. 2018, 25, 32466–32477. https://doi.org/10.1007/s11356-018-3119-3.
  26. El-Sheikh, S.M.; Khedr, T.M.; Amer Hakki, K .; Ismail, A.A.; Badawy, W. A.; Bahnemann, D.W.Visible light activated carbon and nitrogen co-doped mesoporous TiO2 as efficient photocatalyst for degradation of ibuprofen. Sep. Purif . 2017, 258–268, 1383–5866.https://doi.org/10.1016/j.seppur.2016.09.034.
  27. Chen, Y.; Zhang, G.; Ji, Q.; Liu, H.; Qu, J. Triggering of Low-Valence Molybdenum in Multiphasic MoS2 for Effective Reactive Oxygen Species Output in Catalytic Fenton-like Reactions. ACS Appl. Mater. Interfaces 2019, 11, 26781–26788. https://doi.org/10.1021/acsami.9b05978.
  28. Liu W, Wang Y, Ai Z; et al. Hydrothermal synthesis of FeS2 as a high-efficiency Fenton reagent to degrade alachlor via superoxide-mediated Fe (II)/Fe (III) cycle. ACS Appl. Mater. Interfaces 2015, 51, 28534–28544. https://doi.org/10.1021/acsami.5b09919.
  29. Wu, X.; Zhao, H.; Xu, J. Rational synthesis of marcacite FeS2 hollow microspheres for high-rate and long-life sodium ion battery anode. J. Alloys Compd. 2020, 825, 154173. https://doi.org/10.1016/j.jallcom.2020.154173.
  30. Yuan, B.; Luan, W.; Tu, S. One-step synthesis of cubic FeS2 and flower-like FeSe2 particles by a solvothermal reduction process. Dalton Trans. 2012, 41, 772–776. https://doi.org/10.1039/C1DT11176K.
  31. Yue, C.; Zhang, X.; Yin, J.; Zhou, H.; Liu, K.; Liu, X. Highly efficient FeS2@FeOOH core-shell water oxidation electrocatalyst formed by surface reconstruction of FeS2 microspheres supported on Ni foam. Appl. Catal. B-Environ. 2023, 339, 123171. https://doi.org/10.1016/j.apcatb.2023.123171.
  32. Sun, K.; Su, Z.; Yang, J.; Han, Z.; Liu, F.; Lai, Y.; Li, J.; Liu, Y. Fabrication of pyrite FeS2 thin films by sulfurizing oxide precursor films deposited via successive ionic layer adsorption and reaction method. Thin Solid Film. 2013, 542, 123–128. https://doi.org/10.1016/j.tsf.2013.06.091.
  33. Jiang, F.; Peckler, L.T.; Muscat, A.J. Phase Pure Pyrite FeS2 Nanocubes Synthesized Using Oleylamine as Ligand, Solvent, and Reductant. Cryst. Growth Des. 2015, 15, 3565–3572. https://doi.org/10.1021/acs.cgd.5b00751.
  34. White, S.N. Laser Raman spectroscopy as a technique for identification of seafloor hydrothermal and cold seep minerals. Chem. Geol. 2009, 259, 240–252. https://doi.org/10.1016/j.chemgeo.2008.11.008.
  35. Sha, R.; Vishnu, N.; Badhulika, S.J.I.T. Single Step Synthesis of 2-D Marcasite FeS2 Micro-Flowers Based Electrochemical Sensor for Simultaneous Detection of Four DNA Bases. IEEE Trans. Nanotechnol. 2022, 21, 374–379. https://doi.org/10.1109/TNANO.2022.3190223.
  36. Liu, Y.; Jin, W.; Zhao, Y.; Zhang, G.; Zhang, W.J.A.C.B.E. Enhanced catalytic degradation of methylene blue by α-Fe2O3/graphene oxide via heterogeneous photo-Fenton reactions. Appl. Catal. B: Environ. 2017, 206, 642–652. https://doi.org/10.1016/j.apcatb.2017.01.075.
  37. Liu, R.; Wang, Y.; Yang, Y.; Shen, L.; Zhang, B.; Dong, Z.; Gao, C.; Xing, B. New insights into adsorption mechanism of pristine and weathered polyamide microplastics towards hydrophilic organic compounds. Environ. Pollut. 2023, 317, 120818. https://doi.org/10.1016/j.envpol.2022.120818.
  38. Wang, B.; Xu, Z.; Dong, B. Occurrence, fate, and ecological risk of antibiotics in wastewater treatment plants in China: A review. J. Hazard. Mater. 2024, 469, 133925. https://doi.org/10.1016/j.jhazmat.2024.133925.
  39. Zou, Y.; Zhou, C.; Li, Z.; Han, X.; Tong, L.; Liu, T.; Xiong, L.; Bai, L.; Liang, J.; Fan, Y.; et al. Hydrophobic Tetracycline Immobilized in Fibrous Hyaluronan Regulates Adhesive Collagen-Based Hydrogel Stability for Infected Wound Healing. Small 2023, 19, 45. https://doi.org/10.1002/smll.202303414.
  40. Dixon, P.; Chauhan, A. Effect of the surface layer on drug release from delefilcon-A (Dailies Total11®) contact lenses. Int. J. Pharm. 2017, 529, 89–101. https://doi.org/10.1016/j.ijpharm.2017.06.036.
  41. Matilainen, A.; Gjessing, E.T.; Lahtinen, T.; Hed, L.; Bhatnagar, A.; Sillanpaa, M. An overview of the methods used in the characterisation of natural organic matter (NOM) in relation to drinking water treatment. Chemosphere 2011, 83, 1431–1442. https://doi.org/10.1016/j.chemosphere.2011.01.018.
  42. Lin, K.-Y.A.; Lin, J.-T. Ferrocene-functionalized graphitic carbon nitride as an enhanced heterogeneous catalyst of Fenton reaction for degradation of Rhodamine B under visible light irradiation. Chemosphere 2017, 182, 54–64. https://doi.org/10.1016/j.chemosphere.2017.04.152.
  43. Cheng, X.; Liang, L.; Ye, J.; Li, N.; Yan, B.; Chen, G. Influence and mechanism of water matrices on H2O2-based Fenton-like oxidation processes: A review. Sci. Total Environ. 2023, 888, 164814. https://doi.org/10.1016/j.scitotenv.2023.164086.
  44. Zhang, B.-T.; Kuang, L.; Teng, Y.; Fan, M.; Ma, Y. Application of percarbonate and peroxymonocarbonate in decontamination technologies. J. Environ. Sci. 2021, 105, 100–115. https://doi.org/10.1016/j.jes.2020.12.031.
  45. Yang, L.; Xiang, Y.; Jia, F.; Xia, L.; Gao, C.; Wu, X.; Peng, L.; Liu, J.; Song, S. Photo-thermal synergy for boosting photo-Fenton activity with rGO-ZnFe2O4.: Novel photo-activation process and mechanism toward environment remediation. Appl. Catal. B-Environ. 2021, 292, 120198. https://doi.org/10.1016/j.apcatb.2021.120198.
  46. Wang, Y.; Chi, Z.; Chen, C.; Su, C.; Liu, D.; Liu, Y.; Duan, X.; Wang, S. Facet- and defect-dependent activity of perovskites in catalytic evolution of sulfate radicals. Appl. Catal. B-Environ. 2020, 272, 118972. https://doi.org/10.1016/j.apcatb.2020.118972.
  47. Yu, H.; Liu, G.; Jin, R.; Zhou, J. Goethite-humic acid coprecipitate mediated Fenton-like degradation of sulfanilamide: The role of coprecipitated humic acid in accelerating Fe(III)/Fe(II) cycle and degradation efficiency. J. Hazard. Mater. 2021, 403, 124026. https://doi.org/10.1016/j.jhazmat.2020.124026.
  48. Nie, Y.; Zhang, Y.; Nie, X.; Tian, X.; Dai, C.; Shi, J.J.J. Colloidal iron species driven enhanced H2O2 decomposition into hydroxyl radicals for efficient removal of methylene blue from water. J. Hazard. Mater. 2023, 448, 130949. https://doi.org/10.1016/j.jhazmat.2023.130949.
  49. Huang, B.; Yang, C.; Zeng, H.; Zhou, L. Multivalent iron-based magnetic porous biochar from peach gum polysaccharide as a heterogeneous Fenton catalyst for degradation of dye pollutants. Int. J. Biol. Macromol. 2023, 253, 126753. https://doi.org/10.1016/j.ijbiomac.2023.126753.
  50. Mei, S.-C.; Li, L.; Huang, G.-X.; Pan, X.-Q.; Yu, H.-Q. Heterogeneous Fenton water purification catalyzed by iron phosphide (FeP). Water Res. 2023, 241, 120151. https://doi.org/10.1016/j.watres.2023.120151.
  51. Liu, J.; Zhang, Q.; Tian, X.; Hong, Y.; Nie, Y.; Su, N.; Jin, G.; Zhai, Z.; Fu, C.J.C.E.J. Highly efficient photocatalytic degradation of oil pollutants by oxygen deficient SnO2 quantum dots for water remediation. Chem. Eng. J. 2021, 404, 127146. https://doi.org/10.1016/j.cej.2020.127146.
  52. Jin, Z.; Li, Q.; Tang, P.; Li, G.; Liu, L.; Chen, D.; Wu, J.; Chai, Z.; Huang, G.; Chen, X.J.N.A. Copper-doped carbon dots with enhanced Fenton reaction activity for rhodamine B degradation. Nanoscale Adv. 2022, 4, 3073–3082. https://doi.org/10.1039/d2na00269h.
  53. Yang, X.; Zhang, X.; Wang, Z.; Li, S.; Zhao, J.; Liang, G.; Xie, X. Mechanistic insights into removal of norfloxacin from water using different natural iron ore-biochar composites: More rich free radicals derived from natural pyrite-biochar composites than hematite-biochar composites. Appl. Catal. B-Environ. 2019, 255, 117752. https://doi.org/10.1016/j.apcatb.2019.117752.
  54. Nesbitt, H.; Scaini, M.; Hochst, H.; Bancroft, G.; Schaufuss, A.; Szargan, R.J.A.M. Synchrotron XPS evidence for Fe2+-S and Fe3+-S surface species on pyrite fracture-surfaces, and their 3D electronic states. Am. Mineral. 2000, 85, 850–857. https://doi.org/10.2138/am-2000-5-628.
  55. Lu, Z.; Wang, N.; Zhang, Y.; Xue, P.; Guo, M.; Tang, B.; Bai, Z.; Dou, S. Pyrite FeS2@C nanorods as smart cathode for sodium ion battery with ultra-long lifespan and notable rate performance from tunable pseudocapacitance. Electrochim. Acta 2018, 260, 755–761. https://doi.org/10.1016/j.electacta.2017.12.031.
  56. Chen, J.; Zhou, X.; Mei, C.; Xu, J.; Zhou, S.; Wong, C.-P. Pyrite FeS2 nanobelts as high-performance anode material for aqueous pseudocapacitor. Electrochim. Acta 2016, 222, 172–176. https://doi.org/10.1016/j.electacta.2016.10.181.
  57. Ye, Z.; Padilla, J.A.; Xuriguera, E.; Beltran, J.L.; Alcaide, F.; Brillas, E.; Sires, I. A Highly Stable Metal-Organic Framework-Engineered FeS2/C Nanocatalyst for Heterogeneous Electro-Fenton Treatment: Validation in Wastewater at Mild pH. Environ. Sci. Technol. 2020, 54, 4664–4674. https://doi.org/10.1021/acs.est.9b07604.
  58. Morales-Gallardo, M.V.; Ayala, A.M.; Pal, M.; Cortes Jacome, M.A.; Toledo Antonio, J.A.; Mathews, N.R. Synthesis of pyrite FeS2 nanorods by simple hydrothermal method and its photocatalytic activity. Chem. Phys. Lett. 2016, 660, 93–98. https://doi.org/10.1016/j.cplett.2016.07.046.
  59. Zhang, Q.; Li, Y.; Li, H.; Zhang, Y.; Zhang, L.; Zhong, S.; Shu, X. Multi-catalysis of glow discharge plasma coupled with FeS2 for synergistic removal of antibiotic. Chemosphere 2023, 312, 137204. https://doi.org/10.1016/j.chemosphere.2022.137204.
  60. Ma, C.; Liu, Y.; Wang, J.; Evrard Deric, N.T.; Li, Y.; Fan, X.; Peng, W. Facile synthesis of pyrite FeS2 on carbon spheres for high-efficiency Fenton-like reaction. Chemosphere 2024, 355, 141799–141799. https://doi.org/10.1016/j.chemosphere.2024.141799.
  61. Zhu, L.; Wang, H.; Sun, J.; Lu, L.; Li, S. Sulfur Vacancies in Pyrite Trigger the Path to Nonradical Singlet Oxygen and Spontaneous Sulfamethoxazole Degradation: Unveiling the Hidden Potential in Sediments. Environ. Sci. Technol. 2024, 58, 6753–6762. https://doi.org/10.1021/acs.est.3c09316.
  62. Chen, X.; Hu, T.; Zhang, J.; Yang, C.; Dai, K.; Pan, C.; Compounds, Diethylenetriamine synergistic boosting photocatalytic performance with porous g-C3N4/CdS-diethylenetriamine 2D/2D S-scheme heterojunction. J. Alloys Compd. 2021, 863, 158068. https://doi.org/10.1016/j.jallcom.2020.158068.
  63. Zhang, W.; Chen, Y. Experimental determination of conduction and valence bands of semiconductor nanoparticles using Kelvin probe force microscopy. J. Nanoparticle Res. 2013, 15, 1–7. https://doi.org/10.1007/s11051-012-1334-2.