Effect of preparation method of colloidal platinum on performance of 12-tungstosilicate for photocatalytic hydrogen generation

Colloidal platinum nanoparticles, the co-catalyst for hydrogen evolution, were prepared using 12-tungstosilicate as photocatalyst by two methods in which photolysis and reduction reaction took place at the same time and at different time, respectively. For the former, H2PtCl6 was reduced directly to colloidal platinum under irradiation and 12-tungstosilicate would transfer into a new structure compound during the process. For the latter, 12-tungstosilicate was first photoreduced to heteropoly blue anion, and then the blue anion could reduce H2PtCl6 to colloidal platinum under no irradiation. The Pt particle size and reactivity of 12-tungstosilicate were characterized by UV–vis and cyclic voltammetry. Preparation methods affect markedly the Pt particle size and reactivity of 12-tungstosilicate so that the photocatalytic activity and stability for hydrogen evolution are different. The possible mechanism was discussed.

Colloidal platinum nanoparticles for hydrogen evolution were prepared using 12-tungstosilicate as photocatalyst by two methods in which photolysis and reduction reaction took place at different time (method ‘a’) and at the same time (method ‘b’), respectively. The rate of the photocatalytic H2 depends on the number of Pt particles. For method ‘b’, the keggin structure of 12-tungstosilicate is destroyed. Figure optionsDownload as PowerPoint slide