In this work, the simultaneous production of CH<sub>4<sub/> and H<sub>2<sub/> from photocatalytic reforming of glucose aqueous solution on Pd-TiO<sub>2<sub/> catalysts under UV light irradiation by Light-Emitting Diodes (LED) was investigated. The Pd-TiO<sub>2<sub/> catalysts were prepared by the photodeposition method. The Pd content was in the range 0.5-2 wt% and a photodeposition time in the range 15-120 min was used. Pd-TiO<sub>2<sub/> powders were extensively characterized by X-Ray Diffraction (XRD), S<sub>BET<sub/>, X-Ray Fluorescence spectrometry (XRF), UV-Vis Diffuse Reflectance Spectra (UV-Vis DRS), TEM and X-Ray Photoelectron spectroscopy (XPS). It was found that the lower Pd loading (0.5 wt%) and 120 min of photodeposition time allowed us to obtain homogeneously distributed metal nanoparticles of small size; it was also observed that the increase in the metal loading and deposition time led to increasing the Pd<sup>0<sup/> species effectively deposited on the sulfated TiO<sub>2<sub/> surface. Particle size and the oxidation state of the palladium were the main factors influencing the photocatalytic activity and selectivity. The presence of palladium on the sulfated titania surface enhanced the H<sub>2<sub/> and CH<sub>4<sub/> production. In fact, on the catalyst with 0.5 wt% Pd loading and 120 min of photodeposition time, H<sub>2<sub/> production of about 26 μmol was obtained after 3 h of irradiation time, higher than that obtained with titania without Pd (about 8.5 μmol). The same result was obtained for the methane production. The initial pH of the solution strongly affected the selectivity of the system. In more acidic conditions, the production of H<sub>2<sub/> was enhanced, while the CH<sub>4<sub/> formation was higher under alkaline conditions.
Tópico:
Advanced Photocatalysis Techniques
Citaciones:
35
Citaciones por año:
Altmétricas:
0
Información de la Fuente:
FuenteOil & Gas Science and Technology – Revue d’IFP Energies nouvelles