Highly efficient hydrogen generation of BiI3 nanoplates decorated with Ag nanoparticles

Abstract

This work presents the photocatalytic hydrogen generation of BiI3 films when they are exposed under simulated solar irradiation. Those films were fabricated by a simple bath chemical deposition method. The images of Scanning electron microscopy show that the BiI3 films are formed by polycrystalline particles with hexagonal shape and a closer inspection shows that nanoplates grown into them. The performance for the hydrogen generation of BiI3 films synthesized with different times (from 1 to 3 h), BiI3 films decorated with silver nanoparticles (BiI3-Ag) and BiI3 powders were compared. We found that the presence of Ag nanoparticles in the BiI3 films increased the hydrogen generation from 9 mmol/g·h to 14 mmol/g·h because these nanoparticles improved electron conductivity, reduced the amount of defects in the BiI3 films, raised the optical absorption, and produced higher photocurrents (with respect to the BiI3 films without nanoparticles) as confirmed by electrochemical experiments. On the contrast, the BiI3 powders had a poor hydrogen generation rate of only 0.5 mmol/g·h, this was due to the fact that they are formed by nanoplates 10 times bigger than these ones grown on the BiI3 films, consequently, they had lower surface area than the nanoplates in the BiI3 films. A possible mechanism for the hydrogen generation by the BiI3 and BiI3-Ag films is also discussed.