Nb-Doped TiO2 Photocatalysts Used to Reduction of CO2 to Methanol

作者：Nogueira M V; Lustosa G M M M; Kobayakawa Y; Kogler W; Ruiz M; Monteiro Filho E S; Zaghete M A; Perazolli L A

来源：Advances in Materials Science and Engineering, 2018, 2018: 7326240.

DOI：10.1155/2018/7326240

<jats:p>In pursuit of higher photoactivity, Nb-doped TiO<jats:sub>2</jats:sub> powders were evaluated in the reduction of CO<jats:sub>2</jats:sub>. The replacement of Ti by Nb in the crystalline structure of TiO<jats:sub>2</jats:sub> promoted methanol formation. Nb-doped TiO<jats:sub>2</jats:sub> powders were successfully synthesized in Nb concentrations of 0.0, 0.5, 1.0, and 2.5% (w/w = weight/weight) using the Pechini method. The materials were calcined at 500°C for two hours to promote the formation of the anatase crystalline phase. After characterization, the powders were modified through an Nb<jats:sup>0</jats:sup> magnetron sputtering deposition using a metallic target in vacuum conditions of 2 × 10<jats:sup>−3</jats:sup> torr, with a deposition time of 10 minutes, and calcination again at 500°C for two hours. The resulting powders showed a surface area up to 30 m<jats:sup>2</jats:sup>/g. The Pechini method promoted the substitution of Ti<jats:sup>4+</jats:sup> for Nb<jats:sup>4+</jats:sup> as observed using XRD and XPS techniques at the crystalline structure and at the surface of the powder. Furthermore, the presence of Nb<jats:sup>0</jats:sup> was also observed at the powder’s surface. The presence of Nb in the crystalline structure increased the photoactivity of powders when compared to nonmodified TiO<jats:sub>2</jats:sub> powders, while the Nb<jats:sup>0</jats:sup> deposition at the powder’s surface decreased the photoactivity for all the investigated compositions.</jats:p>

• 出版日期2018