Photoinduced Deposition of Platinum from (Bu4N)2[Pt(NO3)6] for a Low Pt-Loading Pt/TiO2Hydrogen Photogeneration Catalyst

An efficient method for the deposition of ionic platinum species PtOxonto a TiO2surface was developed on the basis of light-induced activation of the [Pt(NO3)6]2–anion. The deposited PtOxspecies with an effective Pt oxidation state between +4 and +2 have an oxygen-made environment and include single ion centers {PtOn} and polyatomic ensembles {PtnOm} connected to a TiO2surface with Pt–O–Ti bonds. The resulting PtOx/TiO2materials were tested as photocatalysts for the hydrogen evolution reaction (HER) from a water ethanol mixture and have shown uniquely high activity with the rate of H2evolution achieving 11 mol h–1per gram of Pt, which is the highest result for such materials reported to date. A combination of spectral methods shows that, under HER conditions, reduction of the supported PtOxspecies leads to the formation of well-dispersed nanoparticles of metallic platinum attached on the surface of TiO2by Ti–O–Pt bonds. The high activity of the PtOx/TiO2materials is believed to result from a combination of uniform distribution of small platinum nanoparticles over the titania surface and their close interaction with TiO2.