Alginate as Template in the Preparation of Active Titania Photocatalysts. Issue 2 (10th October 2012)

• Record Type: Journal Article
• Authors: Buaki‐Sogo, Mireia; Serra, Marco; Primo, Ana; Alvaro, Mercedes; Garcia, Hermenegildo
• Is Part Of: ChemCatChem. Volume 5:Issue 2(2013:Feb.)
• Page Start: 513
• Page End: 518
• Publication Date: 2012-10-10
• Subjects: Catalysis -- Periodicals; 541.39505
• DOI: 10.1002/cctc.201200386
• Languages: English
• ISSNs: 1867-3880

Abstract

<abstract abstract-type="main" xml:lang="en"> <title>Abstract</title> <p>A simple and reliable procedure to prepare TiO<sub>2</sub> and Au/TiO<sub>2</sub> 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O<sup>2+</sup> ions in the presence or absence of AuCl<sub>4</sub><sup>−</sup>. The resulting alginate beads containing approximately 25 wt % of Ti and various Au contents are dehydrated by ethanol washings before drying under supercritical CO<sub>2</sub> conditions. The key step in the preparation method is to obtain Au/Ti‐containing alginate aerogels of approximately 700 m<sup>2</sup> g<sup>−1</sup> Brunauer–Emmett–Teller surface area. The surface area of the TiO<sub>2</sub> and Au/TiO<sub>2</sub> samples obtained after calcination of the organic biopolymer at 450 °C under air ranges from 187 to 136 m<sup>2</sup> g<sup>−1</sup>, and the Au content has been varied from 1.3 to 0.05 wt % to optimize the photocatalytic activity of the samples. TiO<sub>2</sub> forms in the anatase phase according to XRD and Raman spectroscopy. The highest activity Au/TiO<sub>2</sub> sample (containing 0.556 wt % 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 TiO<sub>2</sub> P25 sample prepared by means of the conventional deposition–precipitation method.</p> </abstract>