Photocatalytic effects on Au@TiO2 confined in BMIm.NTf2 ionic liquid for hydrogen evolution reactions

We report a photocatalytic device based on gold nanoparticles (AuNPs/TiO2) coated with an ionic liquid (IL) as a very active, stable, and versatile system for hydrogen evolution reactions (HERs) via methanol photo reforming (MPR) and photocatalytic water-splitting (WSR) reaction. The devices prepared by magnetron sputtering yield hybrid materials with direct Au–TiO2 interactions that were subsequently coated with BMIm.NTf2 (IL@Au@TiO2). The IL presence critically enhances the photocatalytic performance given its interaction with the AuNPs and TiO2 surfaces by decreasing the flat band energy levels and the Schottky barrier thickness. The results show an increase in the number of charge carriers yielding a capacitor-like effect generated by interactions of IL and Au@TiO2 particles. Apparent quantum yield (AQY) up to 28.3% under UV irradiation (365 nm) and 22.9% at 405 nm irradiation were observed in the HER employing the as-prepared materials.