Short Communication Impact of metal doping on the activity of Au/CeO 2 catalysts for catalytic abatement of VOCs and CO in waste gases T. Tabakova a, ⁎, D. Dimitrov b , M. Manzoli c , F. Vindigni c , P. Petrova a , L. Ilieva a , R. Zanella d , K. Ivanov b a Institute of Catalysis, Bulgarian Academy of Sciences, 1113 Sofia, Bulgaria b Department of Chemistry, Agricultural University, 4000 Plovdiv, Bulgaria c Department of Chemistry and NIS Centre of Excellence, University of Torino, 10125 Torino, Italy d Centro de Ciencias Aplicadas y Desarrollo Tecnológico Universidad Nacional Autónoma de México. Circuito Exterior S/N, Ciudad Universitaria, C. P. 04510 México D. F., Mexico abstract article info Article history: Received 9 November 2012 Received in revised form 28 January 2013 Accepted 31 January 2013 Available online 15 February 2013 Keywords: Gold catalysts CO oxidation VOC abatement Ceria doped by Fe Mn and Co oxides The catalytic performance in the total oxidation of CO and methanol over gold catalysts supported on ceria doped by different metal oxides (Me = Fe, Mn and Co) was studied and a strong influence of the nature of dopant was observed. The activity towards the oxidation of CO and CH 3 OH was in the order: AuCeCo > AuCe > AuCeFe > AuCeMn. The characterization by XRD and HRTEM evidenced differences in the average size and the distribution of gold particles. AuCeCo catalyst exhibited superior low-temperature CO oxidation activity (100% conversion degree was obtained at 25 °C) and almost 100% total oxidation of CH 3 OH at about 40 °C. Higher hydrogen consumption was estimated by means of TPR over this catalyst. The effect of modification with Co 3 O 4 of Au/CeO 2 catalysts on their CO oxidation activity was further studied by varying of the dopant content (5, 10 and 15 wt.% Co 3 O 4 ). © 2013 Elsevier B.V. All rights reserved. 1. Introduction Gold nanoparticles supported on metal oxides have attracted sig- nificant attention in recent two decades due to their high activity for catalyzing various oxidation and reduction reactions at low tem- peratures [1]. Catalytic oxidation of CO is a subject of considerable in- terest due to its relevance in many industrial applications such as indoor air cleaning, fuel cells, CO 2 lasers and automotive exhaust treatment [2]. In addition to CO, volatile organic compounds (VOCs) contribute to increase of urban air pollution. Catalytic combustion is one of the most promising technologies for the abatement of VOCs [3–12]. During the last years special emphasis has been laid on the re- search and development of more efficient catalysts in order to insure compliance with the new emission restrictions imposed by the legis- lation on pollution control. The oxidation activity of gold catalysts is closely related to the size of the gold nanoparticles and the ability of the support to provide active oxygen species during catalytic reac- tions. For this reason, the selection of support has been proposed to be a critical factor. A suitable support should be able to avoid coales- cence and agglomeration of the gold nanoparticles, as well as to par- ticipate actively in the reaction mechanism by redox cycling of the support metal ions [13]. Ceria is known as a very attractive support material, because of its ability to maintain a high dispersion of the active components and to change the oxidation state of the cation between +3 and +4 depending on the redox conditions, which re- sults in rapid formation and elimination of oxygen vacancy defects. The concentration of oxygen vacancies can be increased by doping of ceria. The dopant cations with ionic radius and electronegativity close to those of cerium cation are thought to be the most appropriate modifiers of structural and chemical properties of ceria. This is related to the ability of the heterocations to cause structural distortions in- side ceria, producing strain into the oxide lattice and favoring oxygen vacancy formation. Promising performance in the preferential CO ox- idation (PROX) reaction of gold catalysts supported on ceria doped by some transition or rare-earth cations has been recently reported [14–16]. Laguna et al. have shown that the oxygen release capability is enhanced when iron is added as a dopant to ceria and Au/FeO x / CeO 2 catalysts demonstrated high activity for total and preferential CO oxidation [17,18]. In fact, the presence of iron in the ceria struc- ture was found to increase Au dispersion by creating sites with an in- creased electronic density, which act in a similar way to oxygen vacancies. Recent studies have shown that high CO oxidation activity during the PROX reaction could be achieved after deposition of gold nanoparticles on α-Mn 2 O 3 [19] or MnO 2 –CeO 2 [20]. Wang et al. have reported that Au/CeO 2 –Co 3 O 4 with appropriate Ce/Co atomic ratio exhibited much higher activity than Au/Co 3 O 4 and Au/CeO 2 [21]. In contrast, Liotta et al. have observed the highest CO oxidation activity of Au/CeO 2 in comparative study of support effect on the Catalysis Communications 35 (2013) 51–58 ⁎ Corresponding author at: Institute of Catalysis, Bulgarian Academy of Sciences, Acad. G. Bonchev St., Block 11, 1113 Sofia, Bulgaria. Tel.: +359 2 979 25 28; fax: +359 2 971 29 67. E-mail address: tabakova@ic.bas.bg (T. Tabakova). 1566-7367/$ – see front matter © 2013 Elsevier B.V. All rights reserved. http://dx.doi.org/10.1016/j.catcom.2013.01.021 Contents lists available at SciVerse ScienceDirect Catalysis Communications journal homepage: www.elsevier.com/locate/catcom