Optimization of conditions for photochemical water cleavage. Aqueous platinum/TiO2 (anatase) dispersions under ultraviolet light

TLDR: In this paper, the authors described the preparation and optimization of a water-cleavage catalyst consisting of Pt/TiO/sub 2/ (P-25 Degussa) and two different methods were used to prepare the catalyst: impregnation followed by reduction and exchange.

Abstract: This article describes the preparation and optimization of a water-cleavage catalyst consisting of Pt/TiO/sub 2/ (P-25 Degussa). Two different methods were used to prepare the catalyst: impregnation followed by reduction (calcination in certain cases) and exchange. H/sub 2/PtCl/sub 6/ and Pt(NH/sub 3/)/sub 4/(OH)/sub 2/ were used as base materials. The efficiency of the catalyst was tested in relation to its ability to mediate H/sub 2/ evolution for water under UV light. The influence of pH, temperature, concentration of Pt, as well as preparation temperature and time of reduction are described. Characterization by electron microscopy (EM), surface area measurements (BET), diffuse reflectance spectroscopy (DRS), hydrodynamic particle radius R/sub h/, and electrophoresis is carried out. It is shown that metal islands with a particle size below 8 Angstrom deposited onto TiO/sub 2/ agglomerates of 3000 < R/sub h/ < 6000 Angstrom are the most active catalytic species. The fate of oxygen produced by conduction band holes is also investigated.