Alginate as Template in the Preparation of Active Titania Photocatalysts

Mireia Buaki-Sogo, Marco Serra, Ana Primo, Mercedes Alvaro, Hermenegildo Garcia

Research output: Contribution to journalArticlepeer-review

Abstract

A simple and reliable procedure to prepare TiO2 and Au/TiO2 samples with high photocatalytic activity for hydrogen generation from water/methanol mixtures is reported, which uses natural alginate as the templating agent. Aqueous solutions of sodium alginate are flocculated as beads by Ti=O2+ ions in the presence or absence of AuCl4 -. The resulting alginate beads containing approximately 25wt% of Ti and various Au contents are dehydrated by ethanol washings before drying under supercritical CO2 conditions. The key step in the preparation method is to obtain Au/Ti-containing alginate aerogels of approximately 700m2g-1 Brunauer-Emmett-Teller surface area. The surface area of the TiO2 and Au/TiO2 samples obtained after calcination of the organic biopolymer at 450°C under air ranges from 187 to 136m2g-1, and the Au content has been varied from 1.3 to 0.05wt% to optimize the photocatalytic activity of the samples. TiO2 forms in the anatase phase according to XRD and Raman spectroscopy. The highest activity Au/TiO2 sample (containing 0.556wt% of Au) prepared by means of the biopolymer templating method was approximately eight times more active for hydrogen generation using a solar simulator than was an analogous Au-containing TiO2 P25 sample prepared by means of the conventional deposition-precipitation method.

Original languageEnglish
Pages (from-to)513-518
Number of pages6
JournalChemCatChem
Volume5
Issue number2
DOIs
Publication statusPublished - 1 Feb 2013
Externally publishedYes

Keywords

  • Alginate
  • Gold
  • Hydrogen
  • Photocatalysis
  • Titanium

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