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Porous Cube‐Aggregated Co 3 O 4 Microsphere‐Supported Gold Nanoparticles for Oxidation of Carbon Monoxide and Toluene
Author(s) -
Yang Huanggen,
Dai Hongxing,
Deng Jiguang,
Xie Shaohua,
Han Wen,
Tan Wei,
Jiang Yang,
Au Chak Tong
Publication year - 2014
Publication title -
chemsuschem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.412
H-Index - 157
eISSN - 1864-564X
pISSN - 1864-5631
DOI - 10.1002/cssc.201400050
Subject(s) - toluene , dispersity , carbon monoxide , materials science , nanoparticle , porosity , microsphere , catalysis , chemical engineering , nuclear chemistry , analytical chemistry (journal) , chemistry , nanotechnology , polymer chemistry , organic chemistry , engineering , composite material
Porous cube‐aggregated monodisperse Co 3 O 4 microspheres and their supported gold ( x Au/Co 3 O 4 microsphere, x =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 3 O 4 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 3 O 4 microspheres. Among the Co 3 O 4 microsphere and x Au/Co 3 O 4 microsphere samples, the 7.4Au/Co 3 O 4 microspheres performed the best, giving T 90 % values (the temperature required for achieving a CO or toluene conversion of 90 % at a weight hourly space velocity of 20 000 mL g −1 h −1 ) 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 3 O 4 microsphere sample. The apparent activation energies obtained over the x Au/Co 3 O 4 microsphere samples were in the ranges of 40.7–53.6 kJ mol −1 for toluene oxidation and 21.6–34.6 kJ mol −1 for CO oxidation. It is concluded that the higher oxygen adspecies concentration, better low‐temperature reducibility, and stronger interaction between gold NPs and Co 3 O 4 as well as the porous microspherical structure were responsible for the excellent catalytic performance of 7.4Au/Co 3 O 4 microsphere.