Photocatalytic H2 generation from ethanol and glucose aqueous solutions by PtOx/TiO2 composites

Abstract

A new straightforward protocol for the deposition of the platinum oxide (PtO–PtO2) particles onto the TiO2 semiconductor via controllable hydrolysis of the sulfuric acid solution of Pt(IV) hydroxide was developed. The developed approach represents a simple and “green” way to prepare the supported Adams-type catalysts. In the constructed composites (PtO2·xH2O/TiO2) the Pt ionic species (hydrated PtO and PtO2 nanoparticles) weakly interact with the titania surface, but under heating the Pt–O–Ti bonds are established, resulting in the stabilization of the Pt(II) ionic state. This state dominates in the obtained catalysts PtOx/TiO2 with a low platinum loading, while at a higher Pt content the metallic Pt particles also appear. The prepared PtOx/TiO2 photocatalysts have been successfully tested in the production of hydrogen under UV light from aqueous solutions of ethanol and glucose, the products of starch biomass processing. Appreciable activity in the production of hydrogen from water/ethanol mixtures was achieved, even at a Pt content of up to 0.05%. PtOx/TiO2 photocatalysts with Pt content of 0.2–0.4 wt% have been successfully used to produce hydrogen from aqueous glucose solutions, and PtOx(0.29)/TiO2 photocatalyst has demonstrated an exceptionally high rate of H2 production per gram of platinum introduced and the quantum efficiency comparable to the highest published values.