Photocatalytic H2 production by ethanol photodehydrogenation: Effect of anatase/brookite nanocomposites composition

•Anatase/brookite nanocomposites can be easily prepared by hydrothermal synthesis.•Anatase/brookite composition depends on water/titanate ratio and time of hydrothermal treatment.•Materials present a polyhedral morphology with well crystallized particles.•Anatase/brookite nanocomposite shows high ethanol photodehydrogenation activity.

In view of the sustainable H2 production, development of more efficient catalysts for photocatalytic reforming of oxygenated compounds is required. In this study, we report the preparation of TiO2 nanocomposite with anatase/brookite composition prepared by hydrothermal treatments of Na-titanate precursor. The anatase/brookite ratio can be modulated changing the synthetic parameters, i.e. precursor/water mass-to volume ratio and hydrothermal treatment duration. The obtained materials present well crystallized particles with polyhedral morphology. The anatase/brookite ratio in the nanocomposite affects the mean size of Pt nanoparticles grown by photodeposition and the photocatalytic activity in H2 production by photodehydrogenation of ethanol, with multiphasic materials presenting smaller Pt nanoparticles and higher H2 production. The present anatase/brookite nanocomposites show higher H2 production normalized to the surface area with respect a reference TiO2 prepared by conventional sol–gel synthesis, suggesting that the present materials might expose a higher fraction of highly reactive facets instead of the most thermodynamically stable.

Graphical abstractAnatase/brookite nanocomposite have been prepared by hydrothermal synthesis. The phase composition can be tuned changing the preparation conditions. After photodeposition of Pt nanoparticles, remarkable H2 production through ethanol photodehydrogenation have been obtained. The data indicate that these materials expose the most reactive facets instead of the most thermodynamically stable.Figure optionsDownload full-size imageDownload as PowerPoint slide