Improved quantum yield for photocatalytic hydrogen generation under visible light irradiation over eosin sensitized TiO2—Investigation of different noble metal loading

In the present study, visible light induced hydrogen generation (>420 nm) over the dye-sensitized M/TiO2 (M = Pt, Ru and Rh) photocatalysts has been achieved in the presence of electron donors such as triethanolamine, acetonitrile and triethylamine. The significant enhancement of quantum yield was achieved via noble metal loading and subsequent dye sensitization of M/TiO2. The highest quantum yield for hydrogen generation was 10.27% under irradiation with a wavelength longer than 420 nm. The strong adsorption of dye eosin has been found to enhance this high efficient hydrogen generation, which is supported by the comparsion results of dye eosin adsorption per square nanometer on noble metal loading TiO2, UV–vis adsorption spectra, activity tests and stability tests. In addition, improvement of adsorption of dye on the catalyst, for example, by multidentate co-ordination complexion, may result in higher photocatalytic efficiency of hydrogen generation under visible light illumination.

Graphical abstractHydrogen evolution from 15% (v/v) DEA–H2O solution under visible light (λ > 420 nm) irradiation over (a) 1.0 wt.% Eo-Rh/TiO2; (b) 1.0 wt.% Eo-Pt/TiO2 and (c) 1.0 wt.% Eo-Ru/TiO2 photocatalysts.Figure optionsDownload full-size imageDownload as PowerPoint slide