Reac Kinet Mech Cat DOI 10.1007/s11144-015-0965-6

Influence of preparation methods on the structure and catalytic performance of nanostructured La0.7Ba0.3Co0.3Ni0.7O3 for CO oxidation Bahareh Niknahad1 • Mohsen Mohsennia1,2 Ali Eliassi3

•

Received: 17 August 2015 / Accepted: 4 December 2015 Ó Akade´miai Kiado´, Budapest, Hungary 2015

Abstract Nano-perovskite oxides La0.7Ba0.3Co0.3Ni0.7O3 were synthesized by the co-precipitation and polymerized complex route based on the Pechini process methods (denoted as LBCN-Cop and LBCN-P, respectively) and employed in the removal of carbon monoxide (CO) from (N2 ? CO ? O2) gas mixture through oxidation. In this paper, the effect of the preparation method on the catalytic activity of nanocatalysts is discussed. The catalysts were characterized by XRD, FTIR, BET, TPR, SEM and EDX techniques. The specific surface area of the prepared catalysts varied from 24.55 (LBCN-Cop) to 34.14 (LBCN-P) m2 g-1. SEM investigations revealed that the LBCN-P nanoparticles were uniform spheres in shape with diameters ranging from 50 to 60 nm, whereas more agglomeration of particles was found for the LBCN-Cop catalyst. The results of catalytic activity measurements showed the superiority of the catalyst sample prepared by the Pechini method for CO oxidation at low temperatures compared with that prepared by the coprecipitation method. Keywords CO oxidation  Nanocatalyst  Pechini method  Co-precipitation  Perovskite-type oxide

& Mohsen Mohsennia [email protected]; [email protected] 1

Department of Chemistry, University of Kashan, 8731751167 Kashan, Iran

2

Institute of Nanoscience and Nanotechnology, University of Kashan, 8731751167 Kashan, Iran

3

Department of Chemical Industries Research, Iranian Research Organization for Science and Technology, 3353136846 Tehran, Iran

123

Reac Kinet Mech Cat

Introduction The catalytic oxidation of carbon monoxide (CO) into carbon dioxide (CO2) is a common practice to CO abatement in many applications such as indoor gas purification, electric power plants, and vehicle exhaust pollution control systems [1]. The CO oxidation over noble metal surfaces is a typical reaction within heterogeneous catalysis, which usually occurs at high temperatures [2, 3]. However, the scarcity and high cost of noble metals have conducted extensive searching works to prepare the low cost catalysts for the catalytic CO oxidation at the lower temperatures. An extensive number of oxide minerals as catalysts has been proposed and investigated by many researchers for CO oxidation. Compared with noble metal catalysts, the perovskite-type metal-oxides of the ABO3 formula have been considered as one of promising alternatives for noble metal catalysts in auto-exhaust treatments due to its high thermal stability, controllable redox ability and low cost [4, 5]. For oxidation reactions, perovskite oxides of the type ABO3 and their respective A1-xA0 xB1-yB0 yO3 substituted counterparts are widely employed in many catalytic reactions [6]. Both A and B cations can be partially substituted, leading to multicomponent oxides (A1-xA0 xB1-yB0 yO3) [7]. Partial substitution of the A site causes lattice defects and abnormal valences in B site cations that usually enhance catalytic activity. The B-site partial substitution brings about synergistic effects and influences the stability of the crystalline structure [8]. The design of efficient catalysts providing better-controlled active sites for fundamental studies of heterogeneous catalysis and developing novel industrial catalysts is the ultimate goal of research on heterogeneous catalysis [9]. Generally, the size, shape, composition, and interface/surface engineering in catalytic materials are the key parameters that are usually considered in synthesis to exhibit the rule of catalyst dependence [10, 11]. Since heterogeneous catalysis usually occurs on solid surfaces providing the appropriate electronic and/or geometric environment, the design of active sites on the surface requires precise control on the atomic scale [12]. Generally, incorporation of the alkaline earth metal of Ba2? in the perovskite structure engenders the generation of electron holes and oxygen vacancies as the charge compensation, which can induce high oxygen mobility derived from the mixed conduction by electrons and oxygen ions. Additionally, the incorporation of Ba in the perovskite structure engenders the large free volume in the lattice, which decreases the activation energy of oxygen ion migration [13]. A modified perovskite catalyst of La0.7Sr0.3Mn0.7Cu0.3O3?k showed 100 % CO conversion at 380 °C [14]. Perovskite catalyst of La0.8Sr0.2Co0.8Cu0.2O3 showed the highest activity for CO conversion higher than 80 % and achieved 100 % CO combustion at 355 °C [15]. The catalytic activity and structural stability of monolithic form of La0.9Ce0.1Co1-xFexO3 perovskite catalysts (x = 0, 0.2, 0.4, 0.6, 0.8 and 1.0) and their Pdpromoted forms were evaluated for reduction of NO, oxidations of CO and hydrocarbons (HC), indicating the CO conversion higher than 90 % at 400 °C [16]. The perovskite-type catalysts have been prepared by common methods, e.g. traditional solid-state reactions, sol–gels, precipitation methods and thermal decomposition [17, 18]. Among them, the classical ceramic solid–solid reaction

123

Reac Kinet Mech Cat

and co-precipitation methods, have frequently used for the synthesis of perovskitetype oxide at high reaction temperature ([900 °C). These methods usually yield perovskite-type oxides with a surface area less than 2 m2 g-1. However, the catalysts may be deactivated due to sintering or crystal growth during their continuous use in high temperature processes [19, 20]. Due to its simplicity and relative low cost, the Pechini method as a solution technique has been considered to produce high purity and homogeneous perovskite catalysts at low synthesis temperature without intermediate grinding [21, 22]. This method combines a metal complex formation with an in situ polymerization process to produce the desired oxide [23]. The catalytic activity and structural properties of perovskite catalysts based on the formation of complexes of alkali metals, alkaline earth metals and transition metals using organic chelating agents have been frequently studied [24, 25]. In the complex polymerization routes based on the Pechini method, commonly, a polyalcohol such as ethylene glycol (EG) is added to establish linkages between the chelates by a polyesterification reaction, resulting in a number of advantages over the popular more expensive sol–gel synthesis techniques [26]. In this work, the comparative effect of synthesized routes of nanocrystalline La0.7Ba0.3Co0.3Ni0.7O3 perovskite catalysts using co-precipitation (LBCN-Cop) and Pechini (LBCN-P) methods on the structural properties and catalytic performance the prepared catalysts have been investigated. The catalytic activity of the prepared nanocatalysts was measured for the CO oxidation reaction at different temperatures from 150 to 400 °C with an inlet gas mixture containing 95 % N2, 1 % CO and 4 % O2. Furthermore, the effect of gas hourly space velocity (GHSV), and O2/CO ratio in the feed composition on the catalytic activity was investigated in detail.

Experimental Chemicals and reagents The following materials were used for perovskite synthesis: lanthanum nitrate hexahydrate La(NO3)36H2O, nickel nitrate hexahydrate Ni(NO3)26H2O, barium nitrate Ba(NO3)2 and cobalt nitrate hexahydrate Co(NO3)26H2O, were of analytical grade and purchased from Merck company. Deionized water was used for the preparation of all solutions. Catalyst preparation Co-precipitation method The La0.7Ba0.3Co0.3Ni0.7O3 nanocatalyst was prepared by the co-precipitation method followed by Ba incorporation by impregnation in the co-precipitated mass (LBCN-Cop). In this method, initially, an aqueous solution of lanthanum nitrate hexahydrate La(NO3)36H2O, nickel nitrate hexahydrate Ni(NO3)26H2O and cobalt nitrate hexahydrate Co(NO3)26H2O was prepared. The prepared solution was heated up to 35 °C and NaOH solution (1 M) was added dropwise to adjust the pH

123

Reac Kinet Mech Cat

of the system to 10. Then, the slurry was aged for 5 h under continuous stirring and after that the mixture was cooled to room temperature, filtered and washed with hot deionized water for several times until the pH of the water became neutral to ensure that no sodium remains trapped in the precipitate. The final product was dried overnight at 80 °C, followed by calcination at 550 °C for 3 h. Afterwards, the desired amounts of barium nitrate Ba(NO3)2 were dissolved separately in deionized water under stirring and then the precipitate powder was added to the prepared solutions under stirring for 4 h at room temperature. The prepared suspensions were dried at 80 °C for 10 h and calcined at 600 °C for 3 h with heating rate of 5 °C min-1. Pechini method A process related to the sol–gel route is the Pechini method. In this method, the La0.7Ba0.3Co0.3Ni0.7O3 nanocatalyst was prepared by the polymerized complex (LBCN-P). Following the usual route, the stoichiometric amounts of analytical grade La(NO3)36H2O, Co(NO3)26H2O, Ni(NO3)26H2O and Ba(NO3)2 solution were prepared separately by dissolving nitrates in deionized water. The solutions were mixed and added into a well-stirred container by addition of citric acid and ethylene glycol in a molar ratio of EG/CA = 5 at constant temperature of 90 °C. The final solution was evaporated until a gel was formed and then the gel was kept in an oven at 90 °C to obtain powder. The resulting powder was calcined at 600 °C for 3 h at air with heating rate 5 °C min-1. Catalyst characterization The BET surface area of the prepared catalysts was determined via nitrogen adsorption at -196 °C using an automated gas adsorption analyzer (Quantachrome Autosorb). Temperature-programmed reduction (TPR) was carried out using an automatic apparatus (Chemisorb 2750, Micrometrics) equipped with a thermal conductivity detector. Before the TPR experiment, the fresh sample (100 mg) was treated under an inert atmosphere at 200 °C for 2 h, and then subjected to a reduction treatment with a heating rate of 10 °C min-1 in a reducing gas flow (22 ml min-1) containing a mixture of H2:Ar (10:90). The crystalline structure of catalysts was determined by X-ray powder diffraction (XRD, PANalytical X’Pert-Pro) using a Cu Ka monochromatized radiation source and a Ni filter in the range 2h = 10°–80°. The crystallite sizes of the catalysts were calculated using the Scherrer equation: D ¼ 0:9k = bcosh

ð1Þ

Here D is the crystallite size, k is the wavelength of incident X-rays (0.15405 nm), b is the peak width at half height and h corresponds to the peak position. The surface morphology and compositional analysis of the catalysts was observed via scanning electron microscopy (SEM) (SEM, Mira3 Tescan instrument) with pre-coating samples with a very thin gold layer. Energy-dispersive X-ray spectroscopy (EDX) was performed by using SAMX instrument with 15 kV beam voltage. The sample

123

Reac Kinet Mech Cat

was coated with gold. FT-IR absorbance spectra were obtained via a Magna-IR 550 Fourier transform infrared spectrophotometer. KBr and 1/100 sample (weight ratio) were mixed and ground into fine powder so as to make into a wafer for measurement. Catalytic activity The catalytic CO oxidation reaction was performed at atmospheric pressure in a fixed-bed reactor. This reactor is fixed vertically inside an electric furnace and a K-type thermocouple is embedded in the middle of catalyst bed to measure the reaction temperature. The flow rates of entering gases were controlled by mass flow controllers. The reaction gas mixture of CO (1.0 %), O2 (4.0 %), and balance N2 was passed continuously through the catalyst bed with flow rate of 250 ml min-1, corresponding to gas hourly space velocity (GHSV) of 30,000 h-1. The catalytic activity tests were subsequently performed at temperatures ranging from 150 to 400 °C using different conditions. The analysis of effluent gases was performed by a gas chromatograph equipped with a TCD detector and a molecular Sieve 5A column, and operated with He as the carrier gas.

Results and discussion Molecular structure Fig. 1 shows the FT-IR spectra of the prepared LBCN-Cop and LBCN-P perovskite catalysts. As shown in this figure, the prepared LBCN perovskite catalysts present two strong and well-defined adsorption bands. The first band at around 600 cm-1 is

Fig. 1 FTIR spectra of a LBCN-P and b LBCN-Cop

123

Reac Kinet Mech Cat

assigned to the stretching vibration of the Co–O bond; the second one at about 400 cm-1 is ascribed to the Co–O bending vibration, indicating the perovskite-type structures [27–29]. As shown in Fig. 1, the FT-IR results further prove that the ABO3 perovskite structures are present and stable after dual substitution as well as the impregnation. Although the signal at around 600 cm-1 can be attributed to different Co oxides. However, the Co oxides can be converted to Co3O4 if calcined at 600 °C in air. Due to no existence of the main diffraction peaks of Co3O4 (31.2°, 36.9° and 65.2°) in the XRD pattern of Fig. 2, the presence of different Co oxides can be ignored. However, the band at 435.93 and 474.5 cm-1 essentially reveals the presence of NiO. For the LBCN-Cop sample, the presence of NiO has intensified the IR peak at 472.77 cm-1 [30, 31], which has also been indicated by the XRD spectrum. Furthermore, the LBCN-P sample exhibits weaker and wider IR vibration bands compared with LBCN-Cop, which suggests that the Pechini method leads to a more symmetric structure units [27, 32, 33]. Crystalline phases and specifics surface area The XRD patterns of the LBCN-Cop and LBCN-P catalysts are shown in Fig. 2 and the results are listed in Table 1. It can be seen that the samples have diffraction peaks at 2h = 23°, 33°, 39°, 40°, 41°, 47°, 53°, 58°, 68° and 69°, which could be indexed to the rhombohedra perovskite structure LaCoO3 (JPCDS 48-0123) [34, 35], indicating that the perovskite structures are well kept after the partial substitution of La and Co by Ba and Ni, respectively. The LBCN-P catalyst was rhombohedra phase after calcination at 600 °C, besides some small formation of La2NiO4 (JCPDF 27-1180). The LBCN-Cop showed some peaks attributed to NiO (JCPDF 78-0643) and La2NiO4. In comparison with the LBCN-Cop sample, the LBCN-P catalyst has lower intensity, indicating a lower degree of crystallinity. This

Fig. 2 XRD patterns of a LBCN-P and b LBCN-Cop catalysts: calcination temperature = 600 °C

123

Reac Kinet Mech Cat Table 1 Structural properties of the La0.7Ba0.3Co0.3Ni0.7O3 catalysts prepared at different methods, calcination temperature: 600 °C Sample code

Method

Average crystallite size (nm)a

Surface area (m2 g-1)b

˚) Lattice parameter (A a=b

c

LBCN-P

Pechini

15.66

34.14

5.59

13.45

LBCN-Cop

Co-precipitation

25.54

24.55

5.51

13.45

a

The LaCoO3 strongest diffraction peaks were chosen for calculating the average crystallite size

b

Calculated by the BET equation

implies that the preparation method is important in the formation of double perovskites crystal. The crystallite sizes calculated by the Scherrer equation and lattice parameters are presented in Table 1. According the obtained results as shown in the inset of Fig. 2, the lattice parameters of the LBCN-P catalyst were larger than that of the LBCN-Cop sample, which was consistent with that the XRD peaks for the LBCN-P samples were at lower 2h values. The crystallite size and specific surface area of LBCN-Cop and LBCN-P are also shown in Table 1. A comparison of particle sizes evaluated from the XRD analysis and specific surface area measurements shows that the surface area of LBCN-P (34.14 m2 g-1) is larger than that of LBCN-Cop (24.55 m2 g-1). This is due to the fact that the Pechini method makes the precursor mixture homogenous and enables facile mass transfer. Morphological analysis The morphologies of the synthesized powders are shown in Fig. 3. The LBCN powders synthesized via the co-precipitation method had irregular shapes and showed more agglomeration. The average size of the LBCN-P particles was smaller than that of the LBCN-Cop particles, which is consistent with that calculated from the XRD results by using the Scherrer equation. On the other hand, the powders prepared via the Pechini synthesis had regular shapes, and the particles had a uniform size distribution around 60 nm. Compositional analysis EDX compositional analysis was carried out for the prepared LBCN catalysts and the results are shown in Fig. 4. The quantitative results (relative atomic concentrations) obtained from the semi quantitative EDX analysis as presented in Table 2 confirm the presence of La, Ba, Co, Ni and O in the prepared catalysts with the approximate structural formula of La0.7Ba0.3Co0.3Ni0.7O3. The EDX test results have been supported by the XRD and IR spectrum.

123

Reac Kinet Mech Cat

Fig. 3 SEM photographs of the catalysts: a LBCN-P, b LBCN-Cop

Temperature-programmed reduction by hydrogen For LBCN samples, the reduction peaks in the H2-TPR profiles are attributed to the reduction of Co?3 to Co?2, Ni?3 to Ni?2, and Co?2 to Co0, together with Ni?2 to Ni0 [33, 34, 36]. On the other hand, the H2-TPR profile of ABO3 perovskite oxides mainly indicate the redox properties of B-site metal cation, and the metal ions at A-site with stable valence (e.g., La3?, Ba2?) is hard to be reduced [28, 36, 37]. The H2-TPR profiles of the prepared LBCN-Cop and LBCN-P perovskite catalysts are plotted in Fig. 5. According to this figure, the reduction of the Co3? to Co2? has been achieved at 342 and 346 °C, respectively, on the LBCN-P and LBCN-Cop

123

Reac Kinet Mech Cat

Fig. 4 EDX pattern of the prepared LBCN

Table 2 Composition (atomic %) of LBCN sample determined by EDX Quantitative results Elt

Line

Int

Error

K

Kr

W%

A%

ZAF formula

Ox %

Cal #

O

Ka

285.6

5.5535

0.1316

0.1166

16.52

57.10

0.7060

0.00

0.00

Co

Ka

50.2

1.0065

0.0497

0.0441

4.36

4.09

1.0100

0.00

0.00

Ni

Ka

126.8

1.0065

0.1586

0.1406

13.22

12.45

1.0637

0.00

0.00

Ba

La

289.0

0.8082

0.2975

0.2637

29.83

12.01

0.8842

0.00

0.00

La

La

329.7

0.8082

0.3626

0.3215

36.07

14.35

0.8913

0.00

0.00

1.0000

0.8865

100.00

100.00

0.00

0.00

catalysts. The shift of reduction peaks of cobalt to lower temperature suggests that the Pechini method promotes the reducibility of Co3? at the low temperature range (150–350 °C) reaction. The second peak of the H2-TPR profile of the LBCN-Cop sample at 414 °C (reduction of Ni3? to Ni2?) has been merged with a third peak at 488 °C (reduction of Co2? and Ni2? to Co0 and Ni0). According to Fig. 5, in a hightemperature range reaction, the reduction of Ni3? to Ni2? and Co2? and Ni2? to Co0 and Ni0 occurring in two steps at 428 and 584 °C in the case of LBCN-P indicates that the reduction peaks is shifted to higher temperatures in comparison with the LBCN-Cop. Based on the XRD patterns, the LBCN-Cop sample shows NiO and some peaks attributed to small formation of La2NiO4 phase. The H2-TPR peaks of NiO and La2NiO4 appear at the high temperatures around 500 and 600 °C, respectively [38,

123

Reac Kinet Mech Cat

Fig. 5 TPR profiles of the a LBCN-Cop and b LBCN-P

Fig. 6 CO conversion as function of temperature for LBCN catalysts prepared at different methods under 1 vol% CO, 4 vol% O2, and balance N2. Amount of catalyst = 0.5 g, total flow = 250 ml min-1

39], which is in good agreement with the obtained results in this work. This confirms that the small formation of NiO and La2NiO4 have no a significant effect on the catalytic performance of the prepared catalysts especially at low temperatures. The obtained results confirm that the catalytic activity mainly depends on chemical structure, degree of crystallinity, particle sizes, and specific surface area of the perovskite catalysts which can be affected by the synthesis route.

123

Reac Kinet Mech Cat

Catalytic activity Fig. 6 shows the effect of temperature on the CO conversion in the catalytic oxidation reaction using the prepared LBCN-P and LBCN-Cop catalysts. The catalytic oxidation tests were performed with a gas mixture containing 1 % CO, 4 % O2, 95 % N2 and GHSV = 30,000 h-1. The effect of preparation method on the catalytic activity of the prepared catalysts for CO oxidation was studied in the 150–400 °C temperature range. The CO oxidation reaction can be characterized by T50 % and T90 % representing the reaction temperature at CO conversion of 50 and 90 %. The T50 % and T90 % of LBCN-P catalyst were 163 and 180 °C, respectively, which can be compared with those for the LBCN-Cop catalyst, i.e. 198 and 335 °C, respectively. According to the obtained results, T50 % and T90 % of the LBCN-P catalyst are 35 and 155 °C less than those for the LBCN-Cop catalyst. It can be concluded that the difference in catalytic activity is attributed to the catalyst preparation method. The various characterization techniques confirmed that LBCNP has lower crystallinity and higher surface area than the LBCN-Cop as shown in Table 1. Generally, the oxidation catalytic activity of the LBCN-P catalyst was higher than that of the LBCN-Cop. The effect of the gas hourly space velocity (GHSV) on the catalytic performance has been examined by varying this parameter in the range of 12,000–72,000 h-1 for the CO oxidation reaction. The catalyst mass of 0.5 g and O2/CO ratio of 4 have been considered for achieving all the experiments at constant temperature (T = 400 °C). According to the obtained results as shown in Fig. 7, the CO conversion decreased from 99 to 96 % for the LBCN-P and 98 to 94 % for the LBCN-Cop when the GHSV varied from 12,000 to 72,000 h-1. Therefore, the CO conversion decreased with increasing GHSV, due to the inverse relationship between GHSV and space time. Lower GHSV improves the transport of reactants to

Fig. 7 Effect of space velocity on the catalytic activity of LBCN perovskites under 1 vol% CO, 4 vol% O2, and balance N2. Amount of catalyst = 0.5 g, T = 400 °C

123

Reac Kinet Mech Cat

the active sites on the catalyst surface, resulting in higher reactant conversion. According to the obtained results in this work, the GHSV between 12,000 and 54,000 h-1 may be considered for the LBCN-P catalyst. Even at the GHSV of 66,000 h-1, LBCN-P presented stable performance without detectable catalyst deactivation. The dependence of CO conversion on O2 concentration in the gas feed is shown in Fig. 8. The catalytic activities of the catalysts prepared via both methods were evaluated at 400 °C with GHSV 30,000 h-1 for various feed compositions (O2/ CO = 1, 4, 16). As shown in Fig. 8 for GHSV = 30,000 h-1, the best results for CO conversion are achieved at O2/CO = 4. As shown in Fig. 8, the CO conversion increases with increasing O2 up to O2/CO = 4. For the CO oxidation reaction (CO ? 1/2 O2), the excess oxygen ratio in reactant feed composition in comparison with stoichiometric ratio, O2/CO = 0.5 is an important factor for achieving high conversion efficiencies. Due to the competition of CO and O2 for adsorption on similar sites of the catalysts and the strong CO adsorption, at the low O2/CO ratio, the O2 adsorption has been decreased on the blanked catalyst surface, resulting in the CO conversion reduction. At the high O2/CO ratio, oxygen blocks CO adsorption sites and, therefore, these sites are not the active sites for CO2 production. At the optimum O2/CO ratio (due to the high catalytic activity, the reaction probabilities of CO ? 1/2 O2 are thought to approach unity), the higher CO conversion can be achieved. The high catalytic activity may be related to the adsorption energies of oxygen, the adsorption/dissociation of O2 on the surface, the parameters of rate-limiting mass transfer, the heats of oxide formation, and the catalyst particle sizes. For GHSV = 30,000 h-1, the O2/CO ratio for achieving the maximum reaction yield is 4. However, when the O2/CO ratio increases to 16, the conversion decreases at least 3 and 5 % for the LBCN-P and LBCN-Cop catalysts respectively.

Fig. 8 Effect of O2/CO ratio on the catalytic activity of LBCN perovskites. Amount of catalyst = 0.5 g, T = 400 °C. Feed compositions: O2/CO = 1, 4, 16

123

Reac Kinet Mech Cat

Conclusions The effect of the preparation method on the catalytic activity of nanoperovskite oxides La0.7Ba0.3Co0.3Ni0.7O3 for the CO oxidation was investigated. Several characterization techniques confirmed that the Pechini method produces lower crystallinity and higher surface area than the co-precipitation method. The morphological properties of the prepared nanocatalysts, which are directly related to the synthesis method (e.g. particle size, specific surface area, size of crystal domain, and etc.), were also evaluated. SEM analysis of the samples, prepared by these methods after calcination at 600 °C, shows that the particles are agglomerated in the co-precipitation method, which confirmed the obtained results by XRD and BET analyses. According to the XRD patterns, the LBCN-Cop sample shows NiO phases (JCPDF 78-0643) and some peaks attributed to small formation of La2NiO4 phases (JCPDF 27-1180). The H2-TPR peaks of NiO and La2NiO4 appear at the high temperatures around 500 and 600 °C, respectively. This confirms that the small formation of NiO and La2NiO4 have no a significant effect on the catalytic performance of the prepared catalysts especially at low temperatures. According to the obtained results, it could be concluded that preparation method has a great impact on the catalytic activity. The results showed that the LBCN-P catalyst has better catalytic activity than that of the prepared the LBCN-Cop. The LBCN-P catalyst possesses the higher specific surface area and has the lowest temperature for 50 % (163 °C) and 90 % (180 °C) conversion of CO than those of the LBCN-Cop (T50 % = 198 and T90 % = 335 °C). According to the obtained results at 400 °C, the conversion of CO decreased with an increase in GHSV, and increased with increasing the O2/CO ratio from 1 to 4. The conversion of CO started to decrease for the both catalysts at O2/CO ratio higher than 4. However, the catalytic activity results showed superiority of the LBCN-P catalyst sample over the LBCN-Cop for CO oxidation at the whole temperature range especially at the low temperatures. Acknowledgments Authors are grateful to University of Kashan, Kashan, Iran, for partial financial support of this work.

References 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12.

Chiu K, Kwong F, Ng D (2012) Microporous Mesoporous Mater 156:1–6 Busca G, Finocchio E, Escribano VS (2012) Appl Catal B 113:172–179 Laguna OH, Centeno MA, Romero-Sarria F, Odriozola JA (2011) Catal Today 172:118–123 Chang LH, Sasirekha N, Rajesh B, Chen YW (2007) Sep Purif Technol 58:211–218 Ma AJ, Wang SZ, Liu C, Xian H, Ding Q, Guo L, Meng M, Tand YS, Tsubakie N, Zhang J, Zheng LR, Lia XG (2014) Appl Catal B 146:24–34 Pecchi G, Dinamarca R, Campos CM, Garcia X, Jimenez R, Fierro JLG (2014) Ind Eng Chem Res 53:10090–10096 Pena MA, Fierro JLG (2001) Chem Rev 101:1981–2017 Arefi Oskoui S, Niaei A, Tseng HH, Salari D, Izadkhah B, Hosseini SA (2013) ACS Comb Sci 15:609–621 Huang K, Chu X, Yuan L, Feng W, Wu X, Wang X, Feng S (2014) Chem Commun 50:9200–9203 Cui CH, Yu SH (2013) Acc Chem Res 46:1427–1437 Debe MK (2012) Nature 486:43–51 Li Y, Shen W (2014) Chem Soc Rev 43:1543–1574

123

Reac Kinet Mech Cat 13. 14. 15. 16. 17. 18. 19. 20. 21. 22. 23. 24. 25. 26. 27. 28. 29. 30. 31. 32. 33. 34. 35. 36. 37. 38. 39.

Watanabe R, Mukawa K, Kojima J, Kikuchi E, Sekine Y (2013) Appl Catal A 462–463:168–177 Ran R, Wu X, Weng D (2006) J Alloys Compd 414:169–174 Seyfi B, Baghalha M, Kazemian H (2009) Chem Eng J 148:306–311 Tanaka H, Mizuno N, Misono M (2003) Appl Catal A 244:371–382 Taguchi H, Yamada S, Nagao M, Ichikawa Y, Tabata K (2002) Mater Res Bull 37:69–76 Sreedhar K, Pavaskar NR (2002) Mater Lett 53:452–455 Tejuca LG, Fierro JLG, Tascon JMD (1989) Adv Catal 36:237–328 Yamazoe N, Teraoka Y (1990) Catal Today 8:175–199 Popa M, Frantti J, Kakihana M (2002) Solid State Ionics 154:437–445 Popa M, Kakihana M (2002) Solid State Ionics 151:251–257 Lin J, Yu M, Lin C, Liu X (2007) J Phys Chem C 111:5835–5845 Spinicci R, Faticanti M, Marini P, De Rossi S, Porta P (2003) J Mol Catal A: Chem 197:147–155 Cushing BL, Kolesnichenko VL, O’Connor CJ (2004) Chem Rev 104:3893–3946 Rezaei M, Alavi SM, Sahebdelfar S, Yan ZF (2009) J Porous Mater 16:497–505 Guo X, Meng M, Dai F, Li Q, Zhang Z, Jiang Z, Zhang S, Huang Y (2013) Appl Catal B 142–143:278–289 Zhu J, Li H, Zhong L, Xiao P, Xu X, Yang X, Zhao Z, Li J (2014) ACS Catal 4:2917–2940 Li X, Zhang HB, Li SJ (1995) Mater Chem Phys 41:41–45 Adekunle AS, Oyekunle JA, Oluwafemi OS, Joshua AO, Makinde WO, Ogunfowokan AO, Eleruja MA, Ebenso EE (2014) Int J Electrochem Sci 9:3008–3021 Saghatforoush LA, Hasanzadeh M, Sanati S, Mehdizadeh R (2012) Bull Korean Chem Soc 33:2613–2618 Wu S, Song C, Bin F, Lv G, Song J, Gong C (2014) Mater Chem Phys 148:181–189 Zhou C, Liu X, Wu C, Wen Y, Xue Y, Chen R, Zhang Z, Shan B, Yin H, Wang WG (2014) Phys Chem Chem Phys 16:5106–5112 Sun S, Yang L, Pang G, Feng S (2011) Appl Catal A 401:199–203 Liang H, Hong Y, Zhu C, Li S, Chen Y, Liu Z, Ye D (2013) Catal Today 201:98–102 Yan X, Huang Q, Li B, Xu X, Chen Y, Zhu S, Shen S (2013) J Ind Eng Chem 19:561–565 De Araujo GC, Lima S, Rangel MDC, Parola VL, Pena MA, De Fierro JLG (2005) Catal Today 107–108:906–912 Kawi S, Kathiraser Y (2015) Front Energy Res 3:1–17 Martinelli DM, Melo DM, Garrido Pedrosa AM, Martinelli AE, Melo MA, Batista MK, Bitencourt RC (2012) Mater Sci Appl 3:363–368

123