Comparison between the efficiency of bare and Pt-loaded TiO2 and ZnIn2S4 for H2 production in the presence of triethanolamine, methanol, furfuryl alcohol used as sacrificial agents

Abstract

The production of H2 from water via photocatalysis is proposed as an effective process especially if sunlight is used as a source of irradiation. To exploit both photogenerated electrons and holes, aqueous solutions containing sacrificial species that function as scavengers of the holes have been used. Sacrificial agents including triethanolamine and methanol are often employed although they trap the holes without turning into valuable partial oxidation products. The use of biomass derivatives such as furfuryl alcohol allows, instead, the simultaneous production of H2 and high value-added compounds. In this work, the photocatalytic performance under simulated sunlight irradiation of ZnIn2S4, a photocatalyst which is relatively new and active under solar irradiation, was compared with that of TiO2 (P25), the most widely used material, in the absence and presence of photodeposited Pt. Bare ZnIn2S4 was found to be more active than P25 for both H2 and furfural production in the presence of furfuryl alcohol, giving rise to about 105 µmol g-1 h-1 of H2 along with a furfuryl alcohol conversion and furfural selectivity of about 49 % and 81 %, respectively. These results are encouraging considering the simplicity of preparation of the photocatalyst and the environment friendly experimental conditions in light of a future large-scale implementation of the process.