Development of SnO2–ZnO thin films as a photocatalyst for obtaining alternative fuels through photocatalytic reactions

Abstract

A SnO2–ZnO photocatalyst was deposited using two different methods, successive ionic layer adsorption and reaction (SILAR) and sputtering. The films were annealed at 400 °C for formation of the SnO2–ZnO. X-ray diffraction results revealed that the bare-SnO2 film was composed of the orthorhombic SnO2 phase but subjecting the film to an annealing treatment yielded tetragonal SnO2 and hexagonal ZnO phases. The films have a nonhomogeneous surface with spherical particles, and surface-particle agglomeration occurred when ZnO was deposited on the surface. Native defects, such as oxygen vacancies, of ZnO and SnO2 allowed hydrogen production, which promoted redox reactions. The combination of these oxides resulted in the stability of the films after a second photocatalytic test. The presence of these defects was corroborated through photoluminescence and X-ray photoelectron spectroscopy measurements. The corresponding results revealed an emission band at 460 nm and a singlet peak at 532 eV, which are associated with the region defects and oxygen-deficient regions, respectively.