Preparation of sulfur hydrophobized plasmonic photocatalyst towards durable superhydrophobic coating material

doi:10.1016/j.jmst.2019.04.046

Abstract

Abstract:

The widely used photocatalytic self-cleaning coating materials are often made of polymers and polymer based composites, where the photocatalyst immobilization occurs with macromolecules. However, these organic polymers are often unstable under exposure to UV irradiation and easily degraded by reactive radicals produced in the photocatalytic reaction. In order to solve this problem, in this paper, we present the facile preparation of a multifunctional coating with dual superhydrophobic and photocatalytic properties, where the fixation and the hydrophobization of the plasmonic Ag-TiO₂ photocatalyst particles with visible light activity was performed with non-water soluble sulfur, which is a cheap and easily available material. The resulted novel nanocomposite with rough and nano-tructured surface roughness (1.25-2.45 nm determined by small-angle X-ray scattering) has sufficient low surface energy (3.3 mJ/m²) for superhydrophobic (θ = 151.1°) properties. Moreover, in contrast of the organic and expensive fluoropolymer based composites, this non-wetting nature was durable, because the measured θ was higher than 150° during the long- term LED (λ_max = 405 nm) light irradiation.

Key words: Nanocomposite, Coating materials, Wetting, Lotus-type structure, Visible light photocatalyst

Emese Lantos, László Mérai, Ágota Deák, Juan Gómez-Pérez, Dániel Sebők, Imre Dékány, Zoltán Kónya, László Janovák. Preparation of sulfur hydrophobized plasmonic photocatalyst towards durable superhydrophobic coating material[J]. J. Mater. Sci. Technol., 2020, 41: 159-167.

Figures/Tables 10

Fig. 1. TEM-micrographs of precipitated sulfur nanoparticles and wetting of spray-coated S-nanoparticle layers with deionized water as a test liquid (a), aqueous dispersion of prepared sulfur nanoparticles upon precipitation and 24 h later (b), size-distribution of precipitated sulfur nanoparticles (c).

Fig. 2. Measured streaming potential values of the 0.01% Ag-TiO2 photocatalyst suspension during the addition of the 0.09% suspension of the sulfur nanoparticles at a pH of 5.00 (a) and the recorded Raman spectra of Ag-TiO2 photocatalyst, sulfur nanoparticles, and Ag-TiO2/S composite sample with superhydrophobic wetting properties (b).

Fig. 3. Powder X-ray diffractograms and aqueous dispersions of Ag-TiO2, S and Ag-TiO2/S.

Fig. 4. I(h) vs. h (a) and h3I( h) vs. h2 (b) plots of the scattering curves of Ag-TiO2 and Ag-TiO2/S powder samples with 60 wt% S-content.

Fig. 5. Apparent static water contact angles on Ag-TiO2/S composite surfaces as a function of S-content. The photograph illustrates the water-repellent behaviour of 90 wt% S-containing composite powder film with water drop coloured with methylene blue dye.

Fig. 6. Evolution of advancing and receding contact angles on spray-coated 90 wt% sulfur-hydrophobized photoreactive Ag-TiO2 layers, as well as the determined total apparent surface free energy (γstot) values before and after 180 min blue LED light illumination (λ = 405 nm).

Fig. 7. SEM micrographs and EDX-mapping of Ag-TiO2/S superhydrophobic surfaces with 90 wt% S-content.

Fig. 8. UV-VIS diffuse-reflectance spectra and photographs of Ag-TiO2, S nanoparticles and Ag-TiO2/S composites with the corresponding S-content (given in wt%).

Fig. 9. Characterization of EtOH decomposition (c0 = 0.36 mM) on pure Ag-TiO2 and sulphur layers, and on Ag-TiO2/S composite film (90 wt% S) under LED light illumination (λ = 405 nm) as the function of illumination time. The composite layer was also measured under dark condition for reference (a). EtOH concentration change on Ag-TiO2/S film after 0, 24, 48, 72, 96 and 168 h continuous LED light irradiation (b).

Fig. 10. Effect of long-term UV-A (blue LED) irradiation on the wetting properties of the organic polymer-based and inorganic sulfur-containing superhydrophobic composite coatings.

References

[1]	A. Fujishima, T.N. Rao, D.A. Tryk, J. Photochem. Photobiol. C Photochem. Rev. 1(2000) 1-21.
[2]	T. Boningari, S.N.R. Inturi, M. Suidan, P.G. Smirniotis, J. Mater. Sci. Technol. 34(2018) 1494-1502.
[3]	W. Liu, Y. Xu, W. Zhou, X. Zhang, X. Cheng, H. Zhao, S. Gao, L. Huo, J. Mater. Sci. Technol. 33(2017) 39-46.
[4]	á. Veres, J. Ménesi, á. Juhász, O. Berkesi, N. ábrahám, G. Bohus, A. Oszkó, G. Pótári, N. Buzás, L. Janovák, I. Dékány, Colloid Polym. Sci. 292(2014) 207-217.
[5]	á. Veres, T. Rica, L. Janovák, M. Dömök, N. Buzás, V. Zöllmer, T. Seemann, A. Richardt, I. Dékány, Catal. Today 181 (2012) 156-162.
[6]	J. Xiong, M.Z. Ghori, B. Herkel, T. Strunskus, U. Schürmann, L. Kienle, F. Faupel,Acta Mater. 74(2014) 1-8.
[7]	á. Deák, L. Janovák, E. Csapó, D. Ungor, I. Pálinkó, S. Puskás, T. Ördög, T. Ricza, I. Dékány, Appl. Surf. Sci. 389(2016) 294-302.
[8]	F. Zhang, C. Zhang, L. Song, R. Zeng, S. Li, H. Cui, J. Mater. Sci. Technol. 31(2015) 1139-1143.
[9]	I. Dékány, L.G. Nagy, J. Colloid Interface Sci. 147(1991) 119-128.
[10]	M. Bleszynski, M. Kumosa, Compos. Sci. Technol. 164(2018) 74-81.
[11]	K. Chen, W. Gou, Xu Le, Y. Zhao, Compos. Sci. Technol. 156(2018) 177-185.
[12]	Z. Caia, L. Shena, X. Wang, Q. Guo, Compos. Sci. Technol. 164(2018) 238-247.
[13]	J. Drelich, Surf. Innov. 1(2013) 248-254.
[14]	P. Devendar, G.F. Yang, op. Curr. Chem. (Cham.) 375 (6) (2017) 82-89.
[15]	M. Ellis, D. Ferree, R. Funt, L. Madden, Plant Dis. 82(1998) 428-439.
[16]	J. Barkauskas, Res. Bull. 42(2007) 1732-1741.
[17]	Sr. Choudhury, S. Roy, A. Goswami, S. Basu, J. Antimicrob, Chemother. 67(2012) 1134-1137.
[18]	W. Zheng, Y.W. Liu, X.G. Hu, C.F. Zhang, Electrochim. Acta 51 (2006) 1330-1340.
[19]	E. Chibowski, Adv. Colloid Interface Sci. 103(2003) 149-172.
[20]	U. Eduok, O. Faye, J. Szpunar, Prog. Org. Coat. 111(2017) 124-163.
[21]	A. Gutbier, Z. Anorg, Allergy Chem. 152(1926) 163.
[22]	P.P. von Weimarn, Kolloidchem. Beihefte 22 (1926) 38.
[23]	M. Raffo, Kolloid-Z 2 (1908) 358.
[24]	R. Steudel, Top. Curr. Chem. 230(2003) 153-166.
[25]	T. Preocanin, N. Kállay, Croat. Chem. Acta 79 (2006) 95-106.
[26]	U. Balachandran, N.G. Eror, J. Solid State Chem. 42(1982) 276-282.
[27]	B. Meyer, Chem. Rev. 76(1976) 367-388.
[28]	M. Ritz, L. Vaculíková, J. Kupková, E. Plevová, L. Bartonová, Vibrat. Spec. 84(2016) 7-15.
[29]	A. Caron, J. Donohue, J. Phys. Chem. 64(1960) 1767-1768.
[30]	A.G. Pinkus, J.S. Kim, J.L. McAtee, C.B. Concilio, J. X-Ray, Am. Chem. Soc. 81(1959) 2652-2654.
[31]	L. Mérai, á. Deák, D. Sebök, E. Csapó, T.S. Kolumbán, B. Hopp, I. Dékány, L. Janovak, Express Polym. Lett. 12(2018) 1061-1071.
[32]	L. Mérai, N. Varga, á. Deák, D. Sebök, I. Szenti, á. Kukovecz, Z. Kónya, I. Dékány, L. Janovák, Catal. Today 328 (2019) 85-90.
[33]	L. Janovák, á. Dernovics, L. Mérai, á. Deák, D. Sebök, E. Csapó, A. Varga, I. Dékány, C. Janáky, Chem. Commun. 54(2018) 650-653.
[34]	á. Deák, L. Janovák, E. Csapó, D. Ungor, I. Pálinkó, S. Puskás, T. Ördög, T. Ricza, I. Dékány, Appl. Surf. Sci. 389(2016) 294-302.
[35]	L. Janovák, á. Deák, Sz.P. Tallósy, D. Sebök, E. Csapó, K. Bohinc, A. Abram, I. Pálinkó, I. Dékány, Surf. Coat. Technol. 326(2017) 316-326.
[36]	H. Xu, C.R. Crick, R.J. Poole, J. Mater. Chem. A 6 (2018) 4458-4465.
[37]	T. Verho, C. Bower, P. Andrew, S. Franssila, O. Ikkala, R.H.A. Ras, Adv. Mater. 23(2011) 673-678.