Direct polymerization of polyheptazine in the interlamelar spaces of titanate nanotubes enhances visible-light response


A hybrid organic–inorganic catalyst of polyheptazine and TiO2 nanotubes was obtained by polymerization of polyheptazine directly on the surface of layered titanate nanotubes (TiNT) at 400 °C; leading to a phase transition from TiNT to TiO2 anatase. This method induces the polymerization in-between the layers of TiNTs, in contrast to what happens on commercial TiO2 nanoparticles (P25), for which polymer adsorption occurs only onto the outer surface. As a result, the hybrid materials exhibit enhanced physical–chemical properties, resulting in improved photocatalytic response; the methylene blue degradation was 1.28-times higher using the hybrid polyheptazine-TiO2 nanotubes as a photocatalyst, in comparison to the use of polyheptazine-P25. Besides, polyheptazine-TiO2 nanotubes show higher photo-electrocatalytic activity than TiNTs, whereas polyheptazine-P25 exhibits lower activity than P25. The lower band-gap energies, zeta potentials and higher surface area make the polyheptazine-TiO2 nanotubes more efficient photocatalysts under visible light in comparison to P25-based nanoparticles.

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  1. 1.

    Li, R.X., Li, T., Zhou, Q.X.: Impact of titanium dioxide (TiO2) modification on its application to pollution treatment—a review. Catalysts 10, 804 (2020)

    CAS  Article  Google Scholar 

  2. 2.

    Awofiranye, O.S., Modise, S.J., Naidoo, E.B.: Overview of polymer-TiO2catalyst for aqueous degradation of pharmaceuticals in heterogeneous photocatalytic process. J. Nanopart. Res. 22, 168 (2020)

    CAS  Article  Google Scholar 

  3. 3.

    Nguyen, T.P., Nguyen, D.L.T., Nguyen, V.H., Le, T.H., Vo, D.V.N., Trinh, Q.T., Bae, S.R., Chae, S.Y., Kim, S.Y., Le, Q.V.: Recent advances in TiO2-based photocatalysts for reduction of CO2 to fuels. Nanomaterials 10, 337 (2020)

    CAS  PubMed Central  Article  PubMed  Google Scholar 

  4. 4.

    Zhao, X.S., Zhang, G., Zhang, Z.H.: TiO2-based catalysts for photocatalytic reduction of aqueous oxyanions: state-of-the-art and future prospects. Environ. Int. 136, 105453 (2020)

    CAS  PubMed  Article  Google Scholar 

  5. 5.

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

    CAS  PubMed  Article  Google Scholar 

  6. 6.

    Yan, L., Zhe, L., Michael, G., Michael, J., Yang Yang, L., Xiaobo, C.: Titanium dioxide nanomaterials for photocatalysis. J. Phys. D 50, 193003 (2017)

    Article  CAS  Google Scholar 

  7. 7.

    Fujishima, A., Zhang, X.T., Tryk, D.A.: TiO2 photocatalysis and related surface phenomena. Surf. Sci. Rep. 63, 515–582 (2008)

    CAS  Article  Google Scholar 

  8. 8.

    Pelaez, M., Nolan, N.T., Pillai, S.C., Seery, M.K., Falaras, P., Kontos, A.G., Dunlop, P.S.M., Hamilton, J.W.J., Byrne, J.A., O'Shea, K., Entezari, M.H., Dionysiou, D.D.: A review on the visible light active titanium dioxide photocatalysts for environmental applications. Appl. Catal. B 125, 331–349 (2012)

    CAS  Article  Google Scholar 

  9. 9.

    Tachibana, Y., Haque, S.A., Mercer, I.P., Durrant, J.R., Klug, D.R.: Electron injection and recombination in dye sensitized nanocrystalline titanium dioxide films: a comparison of ruthenium bipyridyl and porphyrin sensitizer dyes. J. Phys. Chem. B 104, 1198–1205 (2000)

    CAS  Article  Google Scholar 

  10. 10.

    Bavykin, D.V., Walsh, F.C.: Titanate and Titania Nanotubes: Synthesis, Properties and Applications. Royal Society of Chemistry, London (2010)

    Google Scholar 

  11. 11.

    Kasuga, T., Hiramatsu, M., Hoson, A., Sekino, T., Niihara, K.: Formation of titanium oxide nanotube. Langmuir 14, 3160–3163 (1998)

    CAS  Article  Google Scholar 

  12. 12.

    Bavykin, D.V., Friedrich, J.M., Walsh, F.C.: Protonated titanates and TiO2 nanostructured materials: synthesis, properties, and applications. Adv. Mater. 18, 2807–2824 (2006)

    CAS  Article  Google Scholar 

  13. 13.

    Khoobi, A., Attaran, A.M., Yousofi, M., Enhessari, M.: A sensitive lead titanate nano-structured sensor for electrochemical determination of pentoxifylline drug in real samples. J. Nanostruct. Chem. 9, 29–37 (2019)

    CAS  Article  Google Scholar 

  14. 14.

    Tian, J., Zhao, P., Zhang, S., Huo, G., Suo, Z., Yue, Z., Zhang, S., Huang, W., Zhu, B.: Platinum and iridium oxide co-modified TiO2 nanotubes array based photoelectrochemical sensors for glutathione. Nanomaterials 10, 522 (2020)

    CAS  PubMed Central  Article  PubMed  Google Scholar 

  15. 15.

    Wang, Q., Zhu, H., Li, B.: Synergy of Ti-O-based heterojunction and hierarchical 1D nanobelt/3D microflower heteroarchitectures for enhanced photocatalytic tetracycline degradation and photoelectrochemical water splitting. Chem. Eng. J. 378, 122072 (2019)

    CAS  Article  Google Scholar 

  16. 16.

    Dai, Z., Yang, L., Li, Y., Zhao, C., Guo, J., Gao, Z., Song, Y.-Y.: A portable dual-mode sensor based on a TiO2 nanotube membrane for the evaluation of telomerase activity. Chem. Commun. 55, 10571–10574 (2019)

    CAS  Article  Google Scholar 

  17. 17.

    Pugliese, D., Lamberti, A., Bella, F., Sacco, A., Bianco, S., Tresso, E.: TiO2 nanotubes as flexible photoanode for back-illuminated dye-sensitized solar cells with hemi-squaraine organic dye and iodine-free transparent electrolyte. Org. Electron. 15, 3715–3722 (2014)

    CAS  Article  Google Scholar 

  18. 18.

    Bella, F., Lamberti, A., Sacco, A., Bianco, S., Chiodoni, A., Bongiovanni, R.: Novel electrode and electrolyte membranes: towards flexible dye-sensitized solar cell combining vertically aligned TiO2 nanotube array and light-cured polymer network. J. Membr. Sci. 470, 125–131 (2014)

    CAS  Article  Google Scholar 

  19. 19.

    Massaro, A., Munoz-Garcia, A.B., Maddalena, P., Bella, F., Meligrana, G., Gerbaldi, C., Pavone, M.: First-principles study of Na insertion at TiO2 anatase surfaces: new hints for Na-ion battery design. Nanoscale Adv. 2, 2745–2751 (2020)

    CAS  Article  Google Scholar 

  20. 20.

    Bella, F., Muñoz-García, A.B., Colò, F., Meligrana, G., Lamberti, A., Destro, M., Pavone, M., Gerbaldi, C.: Combined structural, chemometric, and electrochemical investigation of vertically aligned TiO2 nanotubes for Na-ion batteries. ACS Omega 3, 8440–8450 (2018)

    CAS  PubMed  PubMed Central  Article  Google Scholar 

  21. 21.

    Alim, S.A., Rao, T.S., Miditana, S.R., Lakshmi, K.V.D.: Efficient and recyclable visible light-active nickel-phosphorus co-doped TiO2 nanocatalysts for the abatement of methylene blue dye. J. Nanostruct. Chem. 10, 211–226 (2020)

    CAS  Article  Google Scholar 

  22. 22.

    Pirsaheb, M., Hossaini, H., Nasseri, S., Azizi, N., Shahmoradi, B., Khosravi, T.: Optimization of photocatalytic degradation of methyl orange using immobilized scoria-Ni/TiO2 nanoparticles. J. Nanostruct. Chem. 10, 143–159 (2020)

    CAS  Article  Google Scholar 

  23. 23.

    Ge, M.Z., Cao, C.Y., Huang, J.Y., Li, S.H., Zhang, S.N., Deng, S., Li, Q.S., Zhang, K.Q., Lai, Y.K.: Synthesis, modification, and photo/photoelectrocatalytic degradation applications of TiO2 nanotube arrays: a review. Nanotechnol. Rev. 5, 75–112 (2016)

    CAS  Article  Google Scholar 

  24. 24.

    Zhang, Y., Jiang, Z., Huang, J., Lim, L.Y., Li, W., Deng, J., Gong, D., Tang, Y., Lai, Y., Chen, Z.: Titanate and titania nanostructured materials for environmental and energy applications: a review. RSC Adv. 5, 79479–79510 (2015)

    CAS  Article  Google Scholar 

  25. 25.

    Wang, Q., Fan, C., Li, G., Luo, J., Li, B.: Unique 1D/3D K2Ti6O13/TiO2 micro-nano heteroarchitectures: controlled hydrothermal crystal growth and enhanced photocatalytic performance for water purification. Catal. Sci. Technol. 9, 7023–7033 (2019)

    CAS  Article  Google Scholar 

  26. 26.

    Souza, J.S., Krambrock, K., Pinheiro, M.V.B., Ando, R.A., Guha, S., Alves, W.A.: Visible-light photocatalytic activity of NH4NO3 ion-exchanged nitrogen-doped titanate and TiO2 nanotubes. J. Mol. Catal. A Chem. 394, 48–56 (2014)

    CAS  Article  Google Scholar 

  27. 27.

    Souza, J.S., Pinheiro, M.V.B., Krambrock, K., Alves, W.A.: Dye degradation mechanisms using nitrogen doped and copper(ii) phthalocyanine tetracarboxylate sensitized titanate and Tio2 nanotubes. J. Phys. Chem. C 120, 11561–11571 (2016)

    CAS  Article  Google Scholar 

  28. 28.

    Souza, J.S., Alves, W.A.: Influence of preparation methodology on the photocatalytic activity of nitrogen doped titanate and TiO2 nanotubes. J. Nanosci. Nanotechnol. 20, 5390–5401 (2020)

    PubMed  Article  PubMed Central  Google Scholar 

  29. 29.

    Buchholcz, B., Plank, K., Mohai, M., Kukovecz, A., Kiss, J., Bertoti, I., Konya, Z.: Morphology conserving high efficiency nitrogen doping of titanate nanotubes by NH3 plasma. Top. Catal. 61, 1263–1273 (2018)

    CAS  Article  Google Scholar 

  30. 30.

    Hu, C.C., Hsu, T.C., Kao, L.H.: One-Step Cohydrothermal Synthesis of nitrogen-doped titanium oxide nanotubes with enhanced visible light photocatalytic activity. Int. J. Photoenergy 2012, 391958 (2011)

    Google Scholar 

  31. 31.

    Hu, C.C., Hsu, T.C., Lu, S.Y.: Effect of nitrogen doping on the microstructure and visible light photocatalysis of titanate nanotubes by a facile cohydrothermal synthesis via urea treatment. Appl. Surf. Sci. 280, 171–178 (2013)

    CAS  Article  Google Scholar 

  32. 32.

    Parayil, S.K., Razzaq, A., Park, S.M., Kim, H.R., Grimes, C.A., In, S.I.: Photocatalytic conversion of CO2 to hydrocarbon fuel using carbon and nitrogen co-doped sodium titanate nanotubes. Appl. Catal. A Gen. 498, 205–213 (2015)

    CAS  Article  Google Scholar 

  33. 33.

    Kong, X.Q., Li, J.Y., Yang, C.W., Tang, Q., Wang, D.: Fabrication of Fe2O3/g-C3N4@N-TiO2 photocatalyst nanotube arrays that promote bisphenol A photodegradation under simulated sunlight irradiation. Sep. Purif. Technol. 248, 116924 (2020)

    CAS  Article  Google Scholar 

  34. 34.

    Zhang, B., Ma, X.H., Ma, J., Zhou, Y.M., Liu, G.C., Ma, D., Deng, Z.H., Luo, M.M., Xin, Y.J.: Fabrication of rGO and g-C(3)N(4)co-modified TiO2 nanotube arrays photoelectrodes with enhanced photocatalytic performance. J. Colloid Interface Sci. 577, 75–85 (2020)

    CAS  PubMed  Article  Google Scholar 

  35. 35.

    Gundogmus, P., Park, J., Ozturk, A.: Preparation and photocatalytic activity of g-C3N4/TiO2 heterojunctions under solar light illumination. Ceram. Int. 46, 21431–21438 (2020)

    CAS  Article  Google Scholar 

  36. 36.

    Nimbalkar, D.B., Ramacharyulu, P., Sahoo, S.R., Chen, J.R., Chang, C.M., Maity, A.N., Ke, S.C.: Dual roles of [NCN]2 on anatase TiO2: a fully occupied molecular gap state for direct charge injection into the conduction band and an interfacial mediator for the covalent formation of heterostructured g-C3N4/a-TiO2 nanocomposite. Appl. Catal. B 273, 119036 (2020)

    CAS  Article  Google Scholar 

  37. 37.

    Wang, Q., Zhang, L.X., Guo, Y.K., Shen, M., Wang, M., Li, B., Shi, J.L.: Multifunctional 2D porous g-C3N4 nanosheets hybridized with 3D hierarchical TiO2 microflowers for selective dye adsorption, antibiotic degradation and CO2 reduction. Chem. Eng. J. 396, 125347 (2020)

    CAS  Article  Google Scholar 

  38. 38.

    Wang, Y., Zhang, Y., Di, M.Y., Fu, L., Pan, H.Z., Zhang, K.Y., Xu, Y.J., Yan, S.C., Zhang, C.F., Du, Y.W., Tang, N.J.: Realization of ultrathin red 2D carbon nitride sheets to significantly boost the photoelectrochemical water splitting performance of TiO2 photoanodes. Chem. Eng. J. 396, 125267 (2020)

    CAS  Article  Google Scholar 

  39. 39.

    Zhang, B., He, X., Ma, X.H., Chen, Q.H., Liu, G.C., Zhou, Y.M., Ma, D., Cui, C.Y., Ma, J., Xin, Y.J.: In situ synthesis of ultrafine TiO2 nanoparticles modified g-C3N4 heterojunction photocatalyst with enhanced photocatalytic activity. Sep. Purif. Technol. 247, 116932 (2020)

    CAS  Article  Google Scholar 

  40. 40.

    Zhang, B., Wang, Q., Zhuang, J., Guan, S., Li, B.: Molten salt assisted in-situ synthesis of TiO2/g-C3N4 composites with enhanced visible-light-driven photocatalytic activity and adsorption ability. J. Photochem. Photobiol. A 362, 1–13 (2018)

    CAS  Article  Google Scholar 

  41. 41.

    Wang, Q., Guo, Q., Wang, L., Li, B.: The flux growth of single-crystalline CoTiO3 polyhedral particles and improved visible-light photocatalytic activity of heterostructured CoTiO3/g-C3N4 composites. Dalton Trans. 45, 17748–17758 (2016)

    CAS  PubMed  Article  Google Scholar 

  42. 42.

    Liebig, J.V.: About some nitrogen compounds. Ann. Pharm. 10, 1–47 (1834)

    Article  Google Scholar 

  43. 43.

    Franklin, E.C.: The ammono carbonic acids. J. Am. Chem. Soc. 44, 486–509 (1922)

    CAS  Article  Google Scholar 

  44. 44.

    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)

    CAS  Article  Google Scholar 

  45. 45.

    Yan, X., Gao, Q., Qin, J., Hui, X., Ye, Z., Li, J., Ma, Z.: A facile method for fabricating TiO2/g-C3N4 hollow nanotube heterojunction and its visible light photocatalytic performance. Mater. Lett. 217, 1–4 (2018)

    CAS  Article  Google Scholar 

  46. 46.

    Yu, S., Wang, Y., Sun, F., Wang, R., Zhou, Y.: Novel mpg-C3N4/TiO2 nanocomposite photocatalytic membrane reactor for sulfamethoxazole photodegradation. Chem. Eng. J. 337, 183–192 (2018)

    CAS  Article  Google Scholar 

  47. 47.

    Huang, Y., Wang, P., Wang, Z., Rao, Y., Cao, J.-J., Pu, S., Ho, W., Lee, S.C.: Protonated g-C3N4/Ti3+ self-doped TiO2 nanocomposite films: room-temperature preparation, hydrophilicity, and application for photocatalytic NOx removal. Appl. Catal. B 240, 122–131 (2019)

    CAS  Article  Google Scholar 

  48. 48.

    Wang, Q., Guan, S., Li, B.: 2D graphitic-C3N4 hybridized with 1D flux-grown Na-modified K2Ti6O13 nanobelts for enhanced simulated sunlight and visible-light photocatalytic performance. Catal. Sci. Technol. 7, 4064–4078 (2017)

    CAS  Article  Google Scholar 

  49. 49.

    Xu, J., Herraiz-Cardona, I., Yang, X., Gimenez, S., Antonietti, M., Shalom, M.: The complex role of carbon nitride as a sensitizer in photoelectrochemical cells. Adv. Opt. Mater. 3, 1052–1058 (2015)

    CAS  Article  Google Scholar 

  50. 50.

    Sun, M., Shen, S., Wu, Z., Tang, Z., Shen, J., Yang, J.: Rice spike-like g-C3N4/TiO2 heterojunctions with tight-binding interface by using sodium titanate ultralong nanotube as precursor and template. Ceram. Int. 44, 8125–8132 (2018)

    CAS  Article  Google Scholar 

  51. 51.

    Nie, Y.-C., Yu, F., Wang, L.-C., Xing, Q.-J., Liu, X., Pei, Y., Zou, J.-P., Dai, W.-L., Li, Y., Suib, S.L.: Photocatalytic degradation of organic pollutants coupled with simultaneous photocatalytic H2 evolution over graphene quantum dots/Mn-N-TiO2/g-C3N4 composite catalysts: performance and mechanism. Appl. Catal. B 227, 312–321 (2018)

    CAS  Article  Google Scholar 

  52. 52.

    Beranek, R., Kisch, H.: Surface-modified anodic TiO2 films for visible light photocurrent response. Electrochem. Commun. 9, 761–766 (2007)

    CAS  Article  Google Scholar 

  53. 53.

    Bledowski, M., Wang, L., Ramakrishnan, A., Khavryuchenko, O.V., Khavryuchenko, V.D., Ricci, P.C., Strunk, J., Cremer, T., Kolbeck, C., Beranek, R.: Visible-light photocurrent response of TiO2-polyheptazine hybrids: evidence for interfacial charge-transfer absorption. Phys. Chem. Chem. Phys. 13, 21511–21519 (2011)

    CAS  PubMed  Article  PubMed Central  Google Scholar 

  54. 54.

    Alves, W., Ribeiro, A.O., Pinheiro, M.V.B., Krarnbrock, K., El Haber, F., Froyer, G., Chauvet, O., Ando, R.A., Souza, F.L., Alves, W.A.: Quenching of photoactivity in phthalocyanine copper(II)-titanate nanotube hybrid systems. J. Phys. Chem. C 115, 12082–12089 (2011)

    CAS  Article  Google Scholar 

  55. 55.

    Beranek, R., Kisch, H.: Tuning the optical and photoelectrochemical properties of surface-modified TiO2. Photochem. Photobiol. Sci. 7, 40–48 (2008)

    CAS  PubMed  Article  PubMed Central  Google Scholar 

  56. 56.

    Newport: application notes: solar simulation. Accessed 3 Sept 2020

  57. 57.

    Claudino, C.H., Kuznetsova, M., Rodrigues, B.S., Chen, C., Wang, Z., Sardela, M., Souza, J.S.: Facile one-pot microwave-assisted synthesis of tungsten-doped BiVO4/WO3 heterojunctions with enhanced photocatalytic activity. Mater. Res. Bull. 125, 110783 (2020)

    CAS  Article  Google Scholar 

  58. 58.

    Souza, H.T.S., Oliveira, S.A.A., Souza, J.S.: Modulating the photocatalytic activity of Ag nanoparticles-titanate nanotubes heterojunctions through control of microwave-assisted synthesis conditions. J. Photochem. Photobiol. A 390, 112264 (2020)

    CAS  Article  Google Scholar 

  59. 59.

    Rodrigues, B.S., Branco, C.M., Corio, P., Souza, J.S.: Controlling bismuth vanadate morphology and crystalline structure through optimization of microwave-assisted synthesis conditions. Cryst. Growth Des. 20, 3673–3685 (2020)

    CAS  Article  Google Scholar 

  60. 60.

    Zhang, M., Jin, Z.S., Zhang, J.W., Guo, X.Y., Yang, H.J., Li, W., Wang, X.D., Zhang, Z.J.: Effect of annealing temperature on morphology, structure and photocatalytic behavior of nanotubed H2Ti2O4(OH)2. J. Mol. Catal. A 217, 203–210 (2004)

    CAS  Article  Google Scholar 

  61. 61.

    Stoltzfus, M.W., Woodward, P.M., Seshadri, R., Klepeis, J.-H., Bursten, B.: Structure and Bonding in SnWO4, PbWO4, and BiVO4: lone pairs vs inert pairs. Inorg. Chem. 46, 3839–3850 (2007)

    CAS  PubMed  Article  PubMed Central  Google Scholar 

  62. 62.

    Tang, H., Lévy, F., Berger, H., Schmid, P.E.: Urbach tail of anatase TiO2. Phys. Rev. B 52, 7771–7774 (1995)

    CAS  Article  Google Scholar 

  63. 63.

    Shao, G.-S., Wang, F.-Y., Ren, T.-Z., Liu, Y., Yuan, Z.-Y.: Hierarchical mesoporous phosphorus and nitrogen doped titania materials: synthesis, characterization and visible-light photocatalytic activity. Appl. Catal. B 92, 61–67 (2009)

    CAS  Article  Google Scholar 

  64. 64.

    Wang, Q., Yang, X., Wang, X., Huang, M., Hou, J.: Synthesis of N-doped TiO2 mesosponge by solvothermal transformation of anodic TiO2 nanotubes and enhanced photoelectrochemical performance. Electrochim. Acta 62, 158–162 (2012)

    CAS  Article  Google Scholar 

  65. 65.

    Rumaiz, A.K., Ali, B., Ceylan, A., Boggs, M., Beebe, T., Shah, S.I.: Experimental studies on vacancy induced ferromagnetism in undoped TiO2. Solid State Commun. 144, 334–338 (2007)

    CAS  Article  Google Scholar 

  66. 66.

    Bavykin, D.V., Friedrich, J.M., Lapkin, A.A., Walsh, F.C.: Stability of aqueous suspensions of titanate nanotubes. Chem. Mater. 18, 1124–1129 (2006)

    CAS  Article  Google Scholar 

  67. 67.

    Grover, I.S., Singh, S., Pal, B.: The preparation, surface structure, zeta potential, surface charge density and photocatalytic activity of TiO2 nanostructures of different shapes. Appl. Surf. Sci. 280, 366–372 (2013)

    CAS  Article  Google Scholar 

  68. 68.

    Liu, W., Sun, W., Borthwick, A.G., Ni, J.: Comparison on aggregation and sedimentation of titanium dioxide, titanate nanotubes and titanate nanotubes-TiO2: influence of pH, ionic strength and natural organic matter. Colloids Surf. A Physicochem. Eng. Asp. 434, 319–328 (2013)

    CAS  Article  Google Scholar 

  69. 69.

    Wang, T., Liu, W., Xiong, L., Xu, N., Ni, J.: Influence of pH, ionic strength and humic acid on competitive adsorption of Pb (II), Cd (II) and Cr (III) onto titanate nanotubes. Chem. Eng. J. 215, 366–374 (2013)

    Article  CAS  Google Scholar 

  70. 70.

    Petryshyn, R.S., Yaremko, Z.M., Soltys, M.N.: Effects of surfactants and pH of medium on zeta potential and aggregation stability of titanium dioxide suspensions. Colloid J. 72, 517–522 (2010)

    CAS  Article  Google Scholar 

  71. 71.

    Wang, Q., Zhang, B., Lu, X., Zhang, X., Zhu, H., Li, B.: Multifunctional 3D K2Ti6O13 nanobelt-built architectures towards wastewater remediation: selective adsorption, photodegradation, mechanism insight and photoelectrochemical investigation. Catal. Sci. Technol. 8, 6180–6195 (2018)

    CAS  Article  Google Scholar 

  72. 72.

    Xiang, Q., Yu, J., Wong, P.K.: Quantitative characterization of hydroxyl radicals produced by various photocatalysts. J. Colloid Interface Sci. 357, 163–167 (2011)

    CAS  PubMed  Article  Google Scholar 

  73. 73.

    Olojo, R.O., Xia, R.H., Abramson, J.J.: Spectrophotometric and fluorometric assay of superoxide ion using 4-chloro-7-nitrobenzo-2-oxa-1,3-diazole. Anal. Biochem. 339, 338–344 (2005)

    CAS  PubMed  Article  Google Scholar 

  74. 74.

    Zhu, K., Gao, H., Hu, G., Shi, Z.: A rapid transformation of titanate nanotubes into single-crystalline anatase TiO2 nanocrystals in supercritical water. J. Supercrit. Fluids 83, 28–34 (2013)

    CAS  Article  Google Scholar 

  75. 75.

    Zou, X.-X., Li, G.-D., Wang, Y.-N., Zhao, J., Yan, C., Guo, M.-Y., Li, L., Chen, J.-S.: Direct conversion of urea into graphitic carbon nitride over mesoporous TiO2 spheres under mild condition. Chem. Commun. 47, 1066–1068 (2011)

    CAS  Article  Google Scholar 

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This work was supported by FAPESP (Grants 2017/11395-7 and 2019/26010-9) and by Coordenação de Aperfeiçoamento de Pessoal de Nível Superior—Brasil (CAPES)—Finance Code 001. The authors also acknowledge Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq). We are thankful to LNNano-CNPEM for the use of TEM and SEM facilities, to LNLS-CNPEM for the XRD experiments and to the Multiusers platform (CEM) at UFABC for instrumental facilities.

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Rodrigues, B.S., Almeida, V.A., Claudino, C.H. et al. Direct polymerization of polyheptazine in the interlamelar spaces of titanate nanotubes enhances visible-light response. J Nanostruct Chem (2020).

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  • Photocatalysis
  • Photoelectrocatalysis
  • Polyheptazine
  • Titanate nanotubes