Characterization and application of self-assembled thin films of polyelectrolytes/TiO2/CdSe for hydrogen production. (29th June 2017)

• Record Type: Journal Article
• Authors: Faria, A.C.R.; Vebber, M.C.; Dal'Acqua, N.; Giovanela, M.; Aguzzoli, C.; Pereira, M.B.; Machado, G.; Crespo, J.S.
• Is Part Of: International journal of hydrogen energy. Volume 42:Number 26(2017)
• Page Start: 16568
• Page End: 16578
• Publication Date: 2017-06-29
• Subjects: Self-assembled thin films -- Hydrogen production -- Semiconductor -- Water splitting; Hydrogen as fuel -- Periodicals; Hydrogène (Combustible) -- Périodiques; Hydrogen as fuel; Periodicals; 665.81
• DOI: 10.1016/j.ijhydene.2017.05.080
• Languages: English
• ISSNs: 0360-3199

Abstract

Abstract: Photocatalysis of water to produce hydrogen gas over titanium dioxide or other semiconductor films, known as water splitting, is a promising alternative using solar energy to obtain a clean fuel. Self-assembled thin films (SATFs) from the physical adsorption of polyelectrolytes and inorganic semiconductor nanoparticles are created by an inexpensive and non-polluting process that gives films with high molecular organization. The aim of this work was to fabricate and characterize SATFs via the layer-by-layer technique using the polyelectrolytes polyallylamine hydrochloride (PAH), poly(acrylic acid) and poly(3, 4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) in combination with titanium dioxide and CdSe nanoparticles and evaluate the application potential of these systems to produce hydrogen gas by solar radiation. The characterization of the SATFs showed that films with positive surface charge present favourable conditions for incorporation of negatively charged CdSe nanoparticles and that alkaline condition favour agglomeration of TiO2 nanoparticles. The best system was composed of (PAH + CdSe) and (PEDOT:PSS + TiO2 100% anatase) in alkaline medium. With a hydrogen gas average production rate of 0.350 μmol h −1 cm −2, the maximum number of layers was optimized at 120 layers, beyond which there was a decrease in photocatalytic activity, reducing the average production rate to 0.07 with the SATF of 160 layers. Moreover, the presence of CdSe increased the hydrogen gas production by 75% when compared to the film containing only titanium dioxide. Graphical abstract: Highlights: Self-assembled thin films present photocatalytic activity for H2 production. Polyelectrolytes and deposition pH significantly affect the resulting film. Optimization of the number of layers was achieved. Small amounts of sensitizer significantly increased TiO2 photoactivity.