Photoelectrochemical Hydrogen Production Using SiC-TiO₂-Sm₂O₃as Electrode

This paper shows the importance of the synergy effect of SiC-TiO 2 -Sm 2 O 3 in order to enhance the efficiency of the charge separation in the hydrogen generation by means of photoelectrochemical process. In this work it is reported the photoelectrochemical hydrogen production from an aqueous solution of sulfuric acid using SiC-TiO 2 -Sm 2 O 3 as photoelectrode. The SiC-TiO 2 -Sm 2 O 3 was prepared by sol-gel method and thermal treated at 600°C with different content of samarium. The physicochemical characteristics of the as-prepared SiC-TiO 2 -Sm 2 O 3 powders were measured by scanning electron microscopy (SEM) coupled with energy dispersive spectroscopy (EDS) analysis, Fourier transform infrared spectroscopy (FTIR), ultraviolet-visible absorption spectroscopy (UV-Vis), Photoluminescence analysis (PL), specific BET surface area analysis ( S BET ) and X-ray diffraction (XRD). Hydrogen was generated on SiC-TiO 2 -Sm 2 O 3 from a sulfuric acid solution by applying a bias potential under UV light irradiation. The produced photocurrent intensities associated with the hydrogen production after 1800 seconds of reaction depended on Sm 2 O 3 concentration, and it was found that hydrogen production increased as Sm 3+ concentration increases, up to about 2.0 wt%, and then decreased. Finally, the percentage of incident photon conversion efficiency (% IPCE) was determined as a function of Sm 2 O 3 concentration and the results showed a maximum value (% IPCE = 4.7) for the sample with 2.0 wt% of Sm 3+ ions.