Physical–chemical property and activity evaluation of LaB 0.5 Co 0.5 O 3 (B = Cr, Mn, Cu) and LaMn x Co 1x O 3 (x = 0.1, 0.25, 0.5) nano perovskites in VOC combustion Seyed Ali Hosseini a,b , Dariush Salari b , Aligholi Niaei b, *, Samira Arefi Oskoui b a Department of Chemistry, Faculty of Science, University of Urmia, Orumiyeh, Iran b Department of Applied Chemistry and Chemical Engineering, Faculty of Chemistry, University of Tabriz, 5166616471 Tabriz, Iran 1. Introduction Air pollution is one of the main concerns of human in 21st century. Volatile organic compounds (VOCs) are of main con- tributors of air pollution and precursors of ozone and photochem- ical smog. Photochemical smog is the reaction between volatile organic compounds and nitrogen oxides in the presence of sunlight. Catalytic remediation of VOCs is considered a suitable technique because of economical and efficiency aspects [1]. As it has been well established in literature, the structure and properties of catalyst play the main effects on catalytic performance [2]. The development of efficient catalysts for the total oxidation of volatile organic compounds is desirable from the view point of the environment protection. Noble metals are active for combustion of volatile organic compounds; however, they are expensive and poison can deactivate them [3]. The promising activity and thermal stability of perovskites in catalytic combustion processes are the main driving force for replacing noble metals for the complete oxidation of hydrocarbons [3–5]. Perovskites are the mixed metal oxides with the general formula of ABO 3 . Lanthanides usually occupy the A-site position, and the first row transition metals are at the B-site. They are cheaper and more stable than noble metals. Some compositions were reported to possess similar or higher activity than Pt- supported catalysts [6]. The high stability of the perovskite structure allows the partial substitution and a consequent creation of structural defects and a change in the oxidation state of the cation to maintain the electro neutrality of the compound. A-site and B-site replacements mainly affect the amount and the nature of adsorbed oxygen, respectively [3,7] and would modify the catalytic behavior of perovskites [8]. In those cases in which the substitution is successfully completed (i.e., all of the substituting cation is incorporated into the perovskite structure without phase segregation), the substitu- tion effects on the catalytic activity are going to depend on both the reagent molecule involved and the oxidation mechanism. The catalytic behavior of perovskites depends on the nature of the B-site cation [9–12]. The B-site ions in ABO 3 can be partially substituted by the other ions (ABB ’ O 3 ), resulting in the modifica- tion of catalytic properties. AB 0.5 B 0 0.5 O 3 (A 2 BB 0 O 6 ) is the most common substituted perovskite. Gallagher et al. [9] have independently reported high activities of LaMn 0.5 Cu 0.5 O 3 for the oxidation of CO and the synergistic effect was explained by the combination of two functions, the activation of oxygen by manganese oxide and that of CO by copper ions. Levasseur and Kaliaguine have studied the catalytic combustion of CH 3 OH, CO, and CH 4 over La 1-y Ce y Co 1-x Fe x O 3 perovskites [10]. Abdolrahmani et al. studied effects of preparation and copper substitution on LaMnO 3 in methane combustion [11] and resulted the introduction of copper improved the activity of the catalyst. We have reported Journal of Industrial and Engineering Chemistry xxx (2013) xxx–xxx A R T I C L E I N F O Article history: Received 5 August 2012 Accepted 25 February 2013 Available online xxx Keywords: LaB 0.5 Co 0.5 O 3 perovskite Sol–gel auto combustion Nano mixed oxides Volatile organic compounds TPR * Corresponding author. Tel.: +98 4113393163; fax: +98 4113340191. E-mail address: niaei@yahoo.com (A. Niaei). G Model JIEC-1259; No. of Pages 7 Please cite this article in press as: S.A. Hosseini, et al., J. Ind. Eng. Chem. (2013), http://dx.doi.org/10.1016/j.jiec.2013.02.034 Contents lists available at SciVerse ScienceDirect Journal of Industrial and Engineering Chemistry jou r n al h o mep ag e: w ww .elsevier .co m /loc ate/jiec 1226-086X/$ – see front matter ß 2013 The Korean Society of Industrial and Engineering Chemistry. Published by Elsevier B.V. All rights reserved. http://dx.doi.org/10.1016/j.jiec.2013.02.034