A novel strategy to produce compact and adherent thin films of SnO2/TiO2 composites suitable for water splitting and pollutant degradation

• Published in: Journal of materials science. Materials in electronics 2019-01, Vol.30 (1), p.167-179
• Main Authors: Joudi, F., Naceur, J. Ben, Ouertani, R., Chtourou, R.
• Format: Article
• Language: English
• Subjects: Characterization and Evaluation of Materials; Chemistry and Materials Science; Composite materials; Dyes; Glass substrates; Materials Science; Mechanical properties; Optical and Electronic Materials; Photocatalysis; Photodegradation; Photoelectric effect; Photoelectric emission; Photoluminescence; Sol-gel processes; Spin coating; Stability; Strategy; Synthesis; Thin films; Tin dioxide; Tin oxides; Titanium dioxide; Water splitting; X ray spectra; X-ray diffraction
• ISSN: 0957-4522; 1573-482X
• DOI: 10.1007/s10854-018-0278-4

SnO 2 /TiO 2 composites have been widely studied as efficient photoanodes by various research groups around the globe. However, in this work, we display a novel and low cost strategy to synthesize thin films of such composites. According to the synthesizing strategy, various amounts of Degussa TiO 2 P25 nanopowder ranging from 0.25 to 1.0 g were mixed to a fixed volume of SnO 2 sol–gel solution. Then, the mixtures were spin-coated on doped tin oxide glass substrates. After a slow annealing at 500 °C, we obtained nanostructured SnO 2 /TiO 2 composite thin films (CTFs). As-prepared CTFs were characterized by the scotch tape test, scanning electron microscope, X-ray diffraction and photoluminescence spectra. Furthermore, photoelectrochemical properties, photocatalytic activities and stability of all SnO 2 /TiO 2 composite based PAs were studied. Results showed that composites with medium TiO 2 amount exhibits more compact and adherent films than bare TiO 2 films. We recorded an optimum situation for films prepared with 0.75 g of TiO 2 . It was proved that the SnO 2 sol–gel method enabled compactness and adhesion of the processed composites. We correlated the photoluminescence intensity to the photocurrent density Jsc. The optimum Jsc, almost equal to 0.9 mA, was obtained in the case of 0.75 g amount of TiO 2 . This electrical performance is nearly nine times higher than that recorded with bare TiO 2 photo-anodes. Moreover, replacing bare TiO 2 photocatalyst by SnO 2 /TiO 2 CTFs brought remarkable improvements to the photocatalytic degradation of methyl orange. Finally both morphological and mechanical properties of the composites were correlated to the stability and reusability of the CTF PAs.