Boosting the performance of TiO2 nanotubes with ecofriendly AgIn5Se8 quantum dots for photoelectrochemical hydrogen generation

Abstract

Photoelectrochemical (PEC) cells composed by ecofriendly quantum dots (QDs) are promising devices for solar-to-hydrogen conversion. In this work, photoanodes of Ti/TiO2 NTs sensitized by ecofriendly AgIn5Se8 (AISe) QDs are prepared and characterized. Two different electrochemical procedures are used on the preparation of the precursor nanomaterials. TiO2 NTs are prepared by Ti plate electrochemical anodization and the colloidal aqueous solutions of AISe QDs are prepared by electrosynthesis, using an electrochemical cavity cell. The photoanodes of Ti/TiO2 NTs are sensitized by the linker-assisted method, i.e., photoanode immersion in the AISe solution during 2 h, 24 h, and 48 h. The immersion time is an important parameter, where longer periods of immersion provided higher photocurrent density and lower electron-transfer resistance. The photoanodes Ti/TiO2 NTs/AISe QDs produce a maximum photocurrent after 24 h of sensitization (125 μA cm−2), being 2.4 times higher than the Ti/TiO2 NTs (54 μA cm−2). The photoelectrochemical hydrogen production shows up be effective, giving an H2 total production of 6.47 μmol cm−2 (3.1 times the amount of H2 produced on Ti/TiO2 NTs) after 3 h of irradiation (Xe lamp 300 W, AM 1.5 G filter, 100 mW cm−2). Therefore, can be expected a potential application of these photoanodes in solar fuel production.