Development of novel TiN–LiAlSiO4/SnS/AuPd multilayer films for H2 generation by photocatalysis

Abstract

TiN–LiAlSiO4/SnS/AuPd multilayer films were deposited on glass substrates using screen-printing and SILAR (successive ionic layer adsorption reaction) methods. The films were used as photocatalysts for H2 generation using a solar simulator source. The incorporation of the SnS provokes the presence of particles of different morphology and size, allowing a better light absorption on the surface of the films. In addition, AuPd nanoparticles were deposited on the multilayer films to improve photocatalytic activity. XRD and TEM analysis revealed that whatever the proportion, the main phase is TiN. The SEM images showed that the electrostatic attraction between TiN and SnS is a key factor that influences the morphology of the films. The optical band-gap values for the films were similar (∼3.86 eV). According to profilometry measurements, the thickness of films varies from 218 to 887 nm, and PL results showed that when the thickness decreases the electron-hole pair recombination processes decrease too. The highest H2 generation was reached by T20:L80/SnS/AuPd, around 99 μmol/m2 after 3 h of irradiation, while T80:L20/SnS/AuPd produces only 33 μmol/m2, and coincidentally, showed lower and higher thickness, respectively. Moreover, the presence of AuPd nanoparticles did not provoke any structural and optical modification on the films. However, it caused the existence of active sites for H2 generation and diminish the electron-hole pair recombination, evidenced by PL analysis. Finally, these results corroborate that the film with a low thickness and higher LiAlSiO4 showed better photocatalytic activity because of the inhibition of the electro-hole pair recombination.