Wavelength (nm)
4. Conclusions
In the present study, ZnO nanorods were synthesized using seed-mediated growth and hydrothermal methods on glass substrates with four different growth times. The ZnO nanorods grown for 6 h have the most aligned and the most perpendicular nanorods to the substrates. It is consistent with the XRD result showing the highest TC value of the (002) plane with the largest crystallite size.
Although the ZnO nanorods grown for 6 h has fewer surface area but it has more (002) facets on the surface that results in the highest photocatalytic efficiency (83% within 45 minutes). This may be due to the exposed polar (002) facets absorb UV radiation more efficiently, promote the reduction of recombination rate, more favorable for oxygen interstitial and facile to the adsorption of OH−
ions and anionic methyl blue molecules. All of these mechanisms work together to enhance the photocatalytic activity of ZnO nanorods.
Acknowledgements
This research study was financially supported by Hibah Publikasi International Terindeks untuk Tugas Akhir Mahasiswa (PITTA) 2017 No.
694/UN2.R31/HKP.05.00/2017 from Universitas Indonesia.
Conflict of Interest
The authors declare that they have no conflict of interest.
References
[1] S. Baruah, R.F. Rafique, J. Dutta, Visible Light Photocatalysis By
51
Tailoring Crystal Defects in Zinc Oxide Nanostructures, Nano. 03 (2008) 399–407. doi:10.1142/S179329200800126X.
[2] J. Kaur, S. Singhal, Facile synthesis of ZnO and transition metal doped ZnO nanoparticles for the photocatalytic degradation of Methyl Orange, Ceram Int. 40 (2014) 7417–7424. doi:10.1016/j.ceramint.2013.12.088.
[3] A. Mauro, Di, M. Fragala, Elena, V. Privitera, G. Impellizzeri, ZnO for application in photocatalysis : From thin fi lms to nanostructures, Mater Sci Semicond Process. 69 (2017). doi:10.1016/j.mssp.2017.03.029.
[4] N. Huang, J. Shu, Z. Wang, M. Chen, C. Ren, W. Zhang, One-step
pyrolytic synthesis of ZnO nanorods with enhanced photocatalytic activity and high photostability under visible light and UV light irradiation, J Alloys Compd. 648 (2015) 919–929. doi:10.1016/j.jallcom.2015.07.039.
[5] X. Li, J. Wang, J. Yang, J. Lang, J. Cao, F. Liu, H. Fan, M. Gao, Y. Jiang, Size-controlled fabrication of ZnO micro/nanorod arrays and their
photocatalytic performance, Mater Chem Phys. 141 (2013) 929–935.
doi:10.1016/j.matchemphys.2013.06.028.
[6] C.C. Wang, J.R. Li, X.L. Lv, Y.Q. Zhang, G.S. Guo, Photocatalytic organic pollutants degradation in metal-organic frameworks, Energy Environ Sci. 7 (2014) 2831–2867. doi:10.1039/c4ee01299b.
[7] S.T. Tan, A.A. Umar, A. Balouch, S. Na, M. Yahaya, C.C. Yap, M.M.
Salleh, I. V Kityk, M. Oyama, Ag − ZnO Nanoreactor Grown on FTO Substrate Exhibiting High Heterogeneous Photocatalytic E ffi ciency, ACS Comb Sci. (2014).
[8] D.R. Shinde, T. Popat S, M.G. Chaskar, K.M. Gadave, Photocatalytic degradation of Dyes in Water by Analytical Reagent Grade Photocatalysts – A comparative study, Drink Eng Sci Discuss. (2017) 1–16.
[9] M. Irani, T. Mohammadi, S. Mohebbi, Photocatalytic Degradation of Methylene Blue with ZnO Nanoparticles ; a Joint Experimental and Theoretical Study, J Mex Chem Soc. 60 (2016) 218–225.
[10] N.A. Putri, V. Fauzia, S. Iwan, L. Roza, A.A. Umar, V. Fauzia, S. Iwan, L.
Roza, A.A. Umar, S. Budi, Mn-doping-induced photocatalytic activity enhancement of ZnO nanorods prepared on glass substrates, Appl Surf Sci.
439 (2017) 285–297. doi:10.1016/j.apsusc.2017.12.246.
[11] A. Di Mauro, M.E. Fragalà, V. Privitera, G. Impellizzeri, ZnO for
application in photocatalysis: From thin films to nanostructures, Mater Sci Semicond Process. 69 (2017) 44–51. doi:10.1016/j.mssp.2017.03.029.
[12] D. Byrne, R. Fath Allah, T. Ben, D. Gonzalez Robledo, B. Twamley, M.O.
Henry, E. McGlynn, Study of Morphological and Related Properties of Aligned Zinc Oxide Nanorods Grown by Vapor Phase Transport on Chemical Bath Deposited Buffer Layers, Cryst Growth Des. 11 (2011) 5378–5386. doi:10.1021/cg200977n.
[13] L. Atourki, K. Bouabid, E. Ihalane, L. Alahyane, H. Kirou, E.E. Hamri, A.
Ihlal, A. Elfanaoui, L. Laanab, Pulse Electrodepositin of ZnO for Thin Absorber Solar Cells, Energy Procedia. 50 (2014) 376–382.
doi:10.1016/j.egypro.2014.06.045.
[14] T. Kawaharamura, H. Nishinaka, S. Fujita, Growth of crystalline zinc oxide
52
thin films by fine-channel-mist chemical vapor deposition, Jpn J Appl Phys. 47 (2008) 4669–4675. doi:10.1143/JJAP.47.4669.
[15] A. Balcha, O.P. Yadav, T. Dey, Photocatalytic degradation of methylene blue dye by zinc oxide nanoparticles obtained from precipitation and sol- gel methods, Environ Sci Pollut Res. 23 (2016) 25485–25493.
doi:10.1007/s11356-016-7750-6.
[16] C. Song, Y. Lin, D. Wang, Z. Hu, Facile synthesis of Ag / ZnO microstructures with enhanced photocatalytic activity, Mater Lett. 64 (2010) 1595–1597. doi:10.1016/j.matlet.2010.04.033.
[17] C. Yern, K. Nadarajah, M. Khalid, Y. Wong, Optical and structural characterization of solution processed zinc oxide nanorods via hydrothermal method, Ceram Int. 40 (2014) 9997–10004.
doi:10.1016/j.ceramint.2014.02.098.
[18] S.T. Tan, A.A. Umar, M.M. Salleh, Synthesis of defect-rich, (001) faceted- ZnO nanorod on a FTO substrate as efficient photocatalysts for
dehydrogenation of isopropanol to acetone, J Phys Chem Solids. 93 (2016) 73–78. doi:10.1016/j.jpcs.2016.02.011.
[19] Z. Yi, J. Luo, X. Ye, Y. Yi, J. Huang, Y. Yi, T. Duan, W. Zhang, Y. Tang, Effect of synthesis conditions on the growth of various ZnO nanostructures and corresponding morphology-dependent photocatalytic activities,
Superlattices Microstruct. 100 (2016) 907–917.
doi:10.1016/j.spmi.2016.10.049.
[20] C. Wang, D. Wu, P. Wang, Y. Ao, J. Hou, J. Qian, Effect of oxygen vacancy on enhanced photocatalytic activity of reduced ZnO nanorod arrays, Appl Surf Sci. 325 (2015) 112–116.
doi:10.1016/j.apsusc.2014.11.003.
[21] A. Ali, X. Zhao, A. Ali, L. Duan, H. Niu, C. Peng, Y. Wang, S. Hou,
Enhanced photocatalytic activity of ZnO nanorods grown on Ga doped seed layer, Superlattices Microstruct. 83 (2015) 422–430.
doi:10.1016/j.spmi.2015.02.031.
[22] D. Klauson, I. Gromyko, T. Dedova, N. Pronina, M. Krichevskaya, O.
Budarnaja, I. Oja Acik, O. Volobujeva, I. Sildos, K. Utt, Study on photocatalytic activity of ZnO nanoneedles, nanorods, pyramids and hierarchical structures obtained by spray pyrolysis method, Mater Sci Semicond Process. 31 (2015) 315–324. doi:10.1016/j.mssp.2014.12.012.
[23] M. Zirak, O. Moradlou, M.R. Bayati, Y.T. Nien, A.Z. Moshfegh, On the growth and photocatalytic activity of the vertically aligned ZnO nanorods grafted by CdS shells, Appl Surf Sci. 273 (2013) 391–398.
doi:10.1016/j.apsusc.2013.02.050.
[24] G. Wang, D. Chen, H. Zhang, J.Z. Zhang, J. Li, Tunable photocurrent spectrum in well-oriented zinc oxide nanorod arrays with enhanced photocatalytic activity, J Phys Chem C. 112 (2008) 8850–8855.
doi:10.1021/jp800379k.
[25] D. Han, J. Cao, S. Yang, J. Yang, B. Wang, Q. Liu, T. Wang, H. Niu, Fabrication of ZnO nanorods/Fe3O4 quantum dots nanocomposites and their solar light photocatalytic performance, J Mater Sci Mater Electron. 26
53
(2015) 7415–7420. doi:10.1007/s10854-015-3372-x.
[26] Z. Li, Y. Huang, X. Wang, D. Wang, X. Wang, F. Han, Three-Dimensional Hierarchical Structures of ZnO Nanorods as a Structure Adsorbent for Water Treatment, J Mater Sci Technol. 33 (2017) 864–868.
doi:10.1016/j.jmst.2016.11.022.
[27] W. Wang, T. Ai, Q. Yu, Electrical and photocatalytic properties of boron- doped ZnO nanostructure grown on PET–ITO flexible substrates by hydrothermal method, Sci Rep. 7 (2017) 42615. doi:10.1038/srep42615.
[28] O.F. Farhat, M.M. Halim, N.M. Ahmed, A.A. Oglat, A.A. Abuelsamen, M.
Bououdina, M.A. Qaeed, A study of the effects of aligned vertically growth time on ZnO nanorods deposited for the first time on Teflon substrate, Appl Surf Sci. 426 (2017) 906–912. doi:10.1016/j.apsusc.2017.07.031.
[29] J.-L. Zhao, X.-M. Li, S. Zhang, C. Yang, X.-D. Gao, W.-D. Yu, Highly (002)-oriented ZnO film grown by ultrasonic spray pyrolysis on ZnO- seeded Si (100) substrate, J Mater Res. 21 (2006) 2185–2190.
doi:10.1557/jmr.2006.0291.
[30] K. Gautam, I. Singh, P.K. Bhatnagar, K.R. Peta, The effect of growth temperature of seed layer on the structural and optical properties of ZnO nanorods, Superlattices Microstruct. 93 (2016) 101–108.
doi:10.1016/j.spmi.2016.03.001.
[31] Y. Ding, F. Zheng, Z. Zhu, Low-temperature seeding and hydrothermal growth of ZnO nanorod on poly(3,4-ethylene dioxythiophene):poly(styrene sulfonic acid), Mater Lett. 183 (2016) 197–201.
doi:10.1016/j.matlet.2016.07.093.
[32] Y.C. Yoon, K.S. Park, S.D. Kim, Effects of low preheating temperature for ZnO seed layer deposited by sol-gel spin coating on the structural
properties of hydrothermal ZnO nanorods, Thin Solid Films. 597 (2015) 125–130. doi:10.1016/j.tsf.2015.11.040.
[33] Y. Lv, Z. Zhang, J. Yan, W. Zhao, C. Zhai, J. Liu, Growth mechanism and photoluminescence property of hydrothermal oriented ZnO nanostructures evolving from nanorods to nanoplates, J Alloys Compd. 718 (2017) 161–
169. doi:10.1016/j.jallcom.2017.05.075.
[34] J. Marselie, V. Fauzia, I. Sugihartono, The role of Mg dopant on the Morphological, Structural and Optical Properties of Mg Doped Zinc Oxide Grown Through Hydrothermal Method, J Phys Conf Ser. 755 (2016) 011001. doi:10.1088/1742-6596/755/1/011001.
[35] S. Kurtaran, S. Aldag, G. Ofofoglu, I. Akyuz, F. Atay, On the role of Al in ultrasonically sprayed ZnO films, Mater Chem Phys. 185 (2017) 137–142.
doi:http://dx.doi.org/10.1016/j.matchemphys.2016.10.016.
[36] M.J. Rivera, E.B. Ramírez, B. Juárez, J. González, J.M. García-León, L.
Escobar-Alarcón, J.C. Alonso, Low temperature-pyrosol-deposition of aluminum-doped zinc oxide thin films for transparent conducting contacts, Thin Solid Films. 605 (2016) 108–115.
doi:http://dx.doi.org/10.1016/j.tsf.2015.11.053.
[37] G. Amin, M.H. Asif, A. Zainelabdin, S. Zaman, O. Nur, M. Willander, Influence of pH, precursor concentration, growth time, and temperature on
54
the morphology of ZnO nanostructures grown by the hydrothermal method, J Nanomater. 2011 (2011). doi:10.1155/2011/269692.
[38] L. Roza, M.Y. a. Rahman, a. a. Umar, M.M. Salleh, Direct growth of oriented ZnO nanotubes by self-selective etching at lower temperature for photo-electrochemical (PEC) solar cell application, J Alloys Compd. 618 (2015) 153–158. doi:10.1016/j.jallcom.2014.08.113.
[39] F. Ahmed, N. Arshi, M.S. Anwar, R. Danish, B.H. Koo, Morphological evolution of ZnO nanostructures and their aspect ratio-induced
enhancement in photocatalytic properties, RSC Adv. 4 (2014) 29249–
29263. doi:10.1039/C4RA02470B.
[40] Y. Wang, R. Shi, J. Lin, Y. Zhu, Enhancement of photocurrent and
photocatalytic activity of ZnO hybridized with graphite-like C3N4, Energy Environ Sci. 4 (2011) 2922–2929. doi:10.1039/c0ee00825g.
[41] S. Duo, Y. Li, Z. Liu, R. Zhong, T. Liu, H. Xu, Preparation of ZnO from 2 D nanosheets to diverse 1 D nanorods and their structure, surface area, photocurrent, optical and photocatalytic properties by simple hydrothermal synthesis, J Alloys Compd. 695 (2017) 2563–2579.
doi:10.1016/j.jallcom.2016.11.162.
[42] S. Maiti, S. Pal, K.K. Chattopadhyay, Recent advances in low temperature{,} solution processed morphology tailored ZnO
nanoarchitectures for electron emission and photocatalysis applications, CrystEngComm. 17 (2015) 9264–9295. doi:10.1039/C5CE01130B.
[43] E. Debroye, J. Van Loon, H. Yuan, K.P.F. Janssen, Z. Lou, S. Kim, T.
Majima, M.B.J. Roeffaers, Facet-Dependent Photoreduction on Single ZnO Crystals, J Phys Chem Lett. 8 (2017) 340–346.
doi:10.1021/acs.jpclett.6b02577.
[44] Y.K. Peng, S.C.E. Tsang, Facet-dependent photocatalysis of nanosize semiconductive metal oxides and progress of their characterization, Nano Today. 18 (2018) 15–34. doi:10.1016/j.nantod.2017.12.011.
[45] T. Lv, L. Pan, X. Liu, T. Lu, G. Zhu, Z. Sun, Enhanced photocatalytic degradation of methylene blue by ZnO-reduced graphene oxide composite synthesized via microwave-assisted reaction, 509 (2011) 10086–10091.
doi:10.1016/j.jallcom.2011.08.045.
[46] S.T. Tan, B.J. Chen, X.W. Sun, W.J. Fan, H.S. Kwok, X.H. Zhang, S.J.
Chua, Blueshift of optical band gap in ZnO thin films grown by metal- organic chemical-vapor deposition, J Appl Phys. 98 (2005) 1–5.
doi:10.1063/1.1940137.
[47] J.-L. Zhao, X.-M. Li, S. Zhang, C. Yang, X. Gao, W.-D. Yu, Highly ( 002 ) -oriented ZnO film grown by ultrasonic spray pyrolysis on ZnO-seeded Si ( 100 ) substrate, J Mater Res - J MATER RES. (2006) 2185–2190.
doi:10.1557/JMR.2006.0291.
[48] S. Rajeh, A. Barhoumi, A. Mhamdi, G. Leroy, B. Duponchel, S. Guermazi, Structural , morphological , optical and photoluminescence properties of Ni- doped ZnO thin films using spray pyrolysis technique, Bull Mater Sci.
39 (2016) 1–26.
[49] A. Sirelkhatim, S. Mahmud, A. Seeni, N.H.M. Kaus, L.C. Ann, S.K.M.
55
Bakhori, H. Hasan, D. Mohamad, Review on zinc oxide nanoparticles:
Antibacterial activity and toxicity mechanism, Nano-Micro Lett. 7 (2015) 219–242. doi:10.1007/s40820-015-0040-x.
[50] J.H. Nobbs, Kubelka- Munk Theory and the Prediction of Reflectance, Rev Prog Color. 15 (1985) 66–75.
[51] B.D. Viezbicke, S. Patel, B.E. Davis, D.P. Birnie, Evaluation of the Tauc method for optical absorption edge determination: ZnO thin films as a model system, Phys Status Solidi. 252 (2015) 1700–1710.
doi:10.1002/pssb.201552007.
[52] R. Rusdi, A.A. Rahman, N.S. Mohamed, N. Kamarudin, N.
Kamarulzaman, Preparation and band gap energies of ZnO nanotubes, nanorods and spherical nanostructures, Powder Technol. 210 (2011) 18–22.
doi:10.1016/j.powtec.2011.02.005.
[53] K. Foo, U. Hashim, K. Muhammad, C. Voon, Sol–gel synthesized zinc oxide nanorods and their structural and optical investigation for
optoelectronic application, Nanoscale Res Lett. 9 (2014) 429–439.
doi:10.1186/1556-276X-9-429.
[54] S. Kandula, P. Jeevanandam, Sun-light-driven photocatalytic activity by ZnO/Ag heteronanostructures synthesized via a facile thermal
decomposition approach, RSC Adv. 5 (2015) 76150–76159.
doi:10.1039/C5RA14179F.
[55] J. Li, L.L. Kerr, Thermodynamic modeling of native defects in ZnO, Opt Mater (Amst). 35 (2013) 1213–1217.
doi:http://dx.doi.org/10.1016/j.optmat.2013.01.014.
[56] S. Bhatia, N. Verma, R.K. Bedi, Sn-doped ZnO nanopetal networks for efficient photocatalytic degradation of dye and gas sensing applications, Appl Surf Sci. 407 (2017) 495–502. doi:10.1016/j.apsusc.2017.02.205.
[57] J.-H. Kim, K.-J. Lee, J.-H. Roh, S.-W. Song, J.-H. Park, I.-H. Yer, B.-M.
Moon, Ga-doped ZnO transparent electrodes with TiO2 blocking layer/nanoparticles for dye-sensitized solar cells, Nanoscale Res Lett. 7 (2012) 11. doi:10.1186/1556-276X-7-11.
[58] M. Ghosh, A.K. Raychaudhuri, Shape transition in ZnO nanostructures and its effect on blue-green photoluminescence, Nanotechnology. 19 (2008) 445704.
[59] A. Rayerfrancis, P.B. Bhargav, N. Ahmed, B. C, S. Dhara, Structural and optical investigations on seed layer assisted hydrothermally grown ZnO nanorods on flat and textured substrates, Silicon. 080054 (2017) 125001.
doi:10.1063/1.4917958.
[60] A. Yengantiwar, R. Sharma, O. Game, A. Banpurkar, Growth of aligned ZnO nanorods array on ITO for dye sensitized solar cell, Curr Appl Phys.
11 (2011) S113–S116. doi:10.1016/j.cap.2010.11.111.
[61] S. Pillai, M. Seery, A Highly Efficient Ag-ZnO Photocatalyst : Synthesis , Properties , and Mechanism, J Phys Chem C. 112 (2008) 13563–13570.
doi:10.1021/jp802729a.
[62] F. Da Silva, O.F. Lopes, A.C. Catto, A. Jr, Hierarchical growth of ZnO nanorods over SnO 2 seed layer : insights into electronic properties from