Highly efficient hydrogen generation of BiI3 nanoplates decorated with Ag nanoparticles

Abstract This work presents the photocatalytic hydrogen generation of BiI 3 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 BiI 3 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 BiI 3 films synthesized with different times (from 1 to 3 h), BiI 3 films decorated with silver nanoparticles (BiI 3 -Ag) and BiI 3 powders were compared. We found that the presence of Ag nanoparticles in the BiI 3 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 BiI 3 films, raised the optical absorption, and produced higher photocurrents (with respect to the BiI 3 films without nanoparticles) as confirmed by electrochemical experiments. On the contrast, the BiI 3 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 BiI 3 films, consequently, they had lower surface area than the nanoplates in the BiI 3 films. A possible mechanism for the hydrogen generation by the BiI 3 and BiI 3 -Ag films is also discussed.