Porous Cube‐Aggregated Co3O4 Microsphere‐Supported Gold Nanoparticles for Oxidation of Carbon Monoxide and Toluene. Issue 6 (5th June 2014)

• Record Type: Journal Article
• Authors: Yang, Huanggen; Dai, Hongxing; Deng, Jiguang; Xie, Shaohua; Han, Wen; Tan, Wei; Jiang, Yang; Au, Chak Tong
• Is Part Of: ChemSusChem. Volume 7:Issue 6(2014:Jun.)
• Page Start: 1745
• Page End: 1754
• Publication Date: 2014-06-05
• Subjects: Green chemistry -- Periodicals; Sustainable engineering -- Periodicals; Chemistry -- Periodicals; Chemical engineering -- Periodicals; 660
• DOI: 10.1002/cssc.201400050
• Languages: English
• ISSNs: 1864-5631

Abstract

<abstract abstract-type="main" xml:lang="en"> <title>Abstract</title> <p>Porous cube‐aggregated monodisperse Co<sub>3</sub>O<sub>4</sub> microspheres and their supported gold (<italic>x</italic>Au/Co<sub>3</sub>O<sub>4</sub> microsphere, <italic>x</italic>=1.6–7.4 wt %) nanoparticles (NPs) were fabricated using the glycerol‐assisted solvothermal and polyvinyl alcohol‐protected reduction methods. Physicochemical properties of the materials were characterized by means of numerous analytical techniques, and their catalytic activities were evaluated for the oxidation of toluene and CO. It is shown that the cubic Co<sub>3</sub>O<sub>4</sub> microspheres were composed of aggregated cubes with a porous structure. The gold NPs with a size of 3.2–3.9 nm were uniformly deposited on the surface of Co<sub>3</sub>O<sub>4</sub> microspheres. Among the Co<sub>3</sub>O<sub>4</sub> microsphere and <italic>x</italic>Au/Co<sub>3</sub>O<sub>4</sub> microsphere samples, the 7.4Au/Co<sub>3</sub>O<sub>4</sub> microspheres performed the best, giving <italic>T</italic><sub>90 %</sub> values (the temperature required for achieving a CO or toluene conversion of 90 % at a weight hourly space velocity of 20 000 mL g<sup>−1</sup> h<sup>−1</sup>) of −8 and 250 °C for CO and toluene oxidation, respectively. In the case of 3.0 vol % water vapor introduction, a positive effect on CO oxidation and a small negative effect on toluene oxidation were observed over the 7.4Au/Co<sub>3</sub>O<sub>4</sub> microsphere sample. The apparent activation energies obtained over the <italic>x</italic>Au/Co<sub>3</sub>O<sub>4</sub> microsphere samples were in the ranges of 40.7–53.6 kJ mol<sup>−1</sup> for toluene oxidation and 21.6–34.6 kJ mol<sup>−1</sup> for CO oxidation. It is concluded that the higher oxygen adspecies concentration, better low‐temperature reducibility, and stronger interaction between gold NPs and Co<sub>3</sub>O<sub>4</sub> as well as the porous microspherical structure were responsible for the excellent catalytic performance of 7.4Au/Co<sub>3</sub>O<sub>4</sub> microsphere.</p> </abstract>