Catalytic decomposition of N2O over CeO2 supported Co3O4 catalysts

Mahammadunnisa, Shaik; Akanksha, Tyagi; Krushnamurty, K.; Subrahmanyam, Ch.

doi:10.1007/s12039-016-1180-3

Cited by 26 publications

(17 citation statements)

References 32 publications

(23 reference statements)

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“…However, the catalytic efficiency of transition metal oxides, involving ceria-based mixed oxides, can be considerably affected by the different counterpart characteristics, such as particle size and morphology. In this regard, engineering the particle size and shape (e.g., nanorods and nanocubes) through the employment of advanced nano-synthesis paths has lately received particular attention [33,[41][42][43]. Interestingly, the support morphology greatly affects the redox properties, oxygen mobility and, subsequently, the catalytic activity of the mixed oxides.…”

Section: Introductionmentioning

confidence: 99%

Ceria Nanoparticles’ Morphological Effects on the N2O Decomposition Performance of Co3O4/CeO2 Mixed Oxides

et al. 2019

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Ceria-based oxides have been widely explored recently in the direct decomposition of N2O (deN2O) due to their unique redox/surface properties and lower cost as compared to noble metal-based catalysts. Cobalt oxide dispersed on ceria is among the most active mixed oxides with its efficiency strongly affected by counterpart features, such as particle size and morphology. In this work, the morphological effect of ceria nanostructures (nanorods (ΝR), nanocubes (NC), nanopolyhedra (NP)) on the solid-state properties and the deN2O performance of the Co3O4/CeO2 binary system is investigated. Several characterization methods involving N2 adsorption at −196 °C, X-ray diffraction (XRD), temperature programmed reduction (TPR), X-ray photoelectron spectroscopy (XPS) and transmission electron microscopy (ΤΕΜ) were carried out to disclose structure–property relationships. The results revealed the importance of support morphology on the physicochemical properties and the N2O conversion performance of bare ceria samples, following the order nanorods (NR) > nanopolyhedra (NP) > nanocubes (NC). More importantly, Co3O4 impregnation to different carriers towards the formation of Co3O4/CeO2 mixed oxides greatly enhanced the deN2O performance as compared to bare ceria samples, without, however, affecting the conversion sequence, implying the pivotal role of ceria support. The Co3O4/CeO2 sample with the rod-like morphology exhibited the best deN2O performance (100% N2O conversion at 500 °C) due to its abundance in Co2+ active sites and Ce3+ species in conjunction to its improved reducibility, oxygen kinetics and surface area.

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Section: Introductionmentioning

confidence: 99%

Ceria Nanoparticles’ Morphological Effects on the N2O Decomposition Performance of Co3O4/CeO2 Mixed Oxides

et al. 2019

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“…This distribution is well aligned with the XRD data of the two samples. Moreover, the phase identification as shown in Figure 7d indicates the presence of lattice fringe spacing of 0.24 nm (311) [50,51] and 0.28 nm (220), which confirms the characteristic lattice structure of Co 3 O 4 [50]. The SEM and TEM images of CoOxHy(H), Co3O4, Co3O4(H) and CoO(H) samples are shown in Figure 7.…”

Section: Thermal and Structural Properties Of Catalystsmentioning

confidence: 61%

Effect of Hydrazine Pretreatment on the Activity, Stability and Active Sites of Cobalt Species for Preferential Oxidation (PROX) of CO in H2-Rich Stream

2019

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The as-prepared (Co3O4) and hydrazine-treated (Co3O4(H)) cobalt catalysts were prepared using the precipitation method and evaluated at a temperature range of 40–220 °C for preferential oxidation (PROX) of CO in excess hydrogen. An improved surface reducibility with smaller crystallite size was noted on hydrazine-treated cobalt species (i.e., Co3O4(H) catalyst), which indicates some surface transformation. This finding correlates with the surface roughness formation (as depicted by scanning electron microscope (SEM) and transmission electron microscope (TEM) data), which was further confirmed by an increase in the Brunauer–Emmett–Teller (BET) surface area. The mesoporous structure of the Co3O4(H) catalyst remained intact, as compared to that of the Co3O4 catalyst. Interestingly, the in situ treatment of the standalone Co3O4(H) catalyst decreased the maximum CO conversion temperature (T100%) from 160 °C (over Co3O4) to 100 °C, with good selectivity. The Co3O4(H) catalyst showed good stability, with approximately 85% CO conversion at 100 °C for 21 h, as compared to a faster deactivation of the Co3O4 catalyst. However, the Co3O4(H) catalyst was unstable in both CO2 and the moisture environment. Based on the evaluation of spent hydrazine-treated (CoO(H)) cobalt catalyst, the high PROX activity is associated with the formation of Co3+ species as confirmed by X-ray diffraction (XRD), X-ray photoelectron spectra (XPS), and temperature-programmed reduction (TPR) data.

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“…As displayed in the SEM image in Figure b, the resultant MnCo 2 O 4 products are uniform and well‐dispersed microspheres. Dispersion and surface area of catalyst promote catalyst activity are as reported previously …”

Section: Resultsmentioning

confidence: 99%

“…Dispersion and surface area of catalyst promote catalyst activity are as reported previously. [24] Energy-dispersive X-ray analysis (EDX)…”

Section: Bet Surface Area Measurementmentioning

confidence: 99%

Transition metals cobaltites spinel for depollution of NO_x emissions using SCR technology

et al. 2017

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The catalytic performances of various transition metal (M = Cu, Mn, and Ni) cobaltites prepared by the nanocasting method were investigated for the selective catalytic reduction (SCR) of NO under lean burn conditions. KIT‐6 was used as a hard template in the nanocasting method for preparation of catalysts. The catalyst samples were characterized by various techniques such as XRD, low‐temperature N2 physisorption, SEM‐EDS, and XPS. The catalysts were examined for the SCR of NO by NH3 and H2‐LPG in a packed bed tubular flow reactor under the following reaction conditions: 500 ppm NO, 8 % O2, (0.1 % NH3) or (1000 ppm LPG, 1 % H2) in Ar with 200 mg catalyst. The inlet and outlet gases of the reactor were analyzed by an Eco Physics CLD 62 chemiluminescence NO/NOx analyzer and online GC. NO and NO2 measurements were done by an Eco Physics CLD 62 chemiluminescence NO/NOx analyzer. Two separate GCs equipped with Porapak Q/capillary columns and FID/ECD detectors were used to analyze the hydrocarbons/−N2O respectively. The addition of 1 % H2 with LPG promoted NO reduction at a remarkably low temperature. It was found that the nature of the dispersed metal strongly affects the light‐off temperature (52 °C) and enhances NO conversion. The oxygen‐deficient MnCo2O4 spinel structure enhanced NO reduction (87.1 %) at a lower temperature of 250 °C as compared to Cu and Ni cobaltites using H2‐LPG‐SCR. The H2‐LPG reductant showed the best de‐NOx activity and the order of catalyst activity followed the sequence: MnCo2O4 > CuCo2O4 > NiCo2O4.

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Catalytic decomposition of N2O over CeO2 supported Co3O4 catalysts

Cited by 26 publications

References 32 publications

Ceria Nanoparticles’ Morphological Effects on the N2O Decomposition Performance of Co3O4/CeO2 Mixed Oxides

Ceria Nanoparticles’ Morphological Effects on the N2O Decomposition Performance of Co3O4/CeO2 Mixed Oxides

Effect of Hydrazine Pretreatment on the Activity, Stability and Active Sites of Cobalt Species for Preferential Oxidation (PROX) of CO in H2-Rich Stream

Transition metals cobaltites spinel for depollution of NO_x emissions using SCR technology

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Catalytic decomposition of N2O over CeO2 supported Co3O4 catalysts

Cited by 26 publications

References 32 publications

Ceria Nanoparticles’ Morphological Effects on the N2O Decomposition Performance of Co3O4/CeO2 Mixed Oxides

Ceria Nanoparticles’ Morphological Effects on the N2O Decomposition Performance of Co3O4/CeO2 Mixed Oxides

Effect of Hydrazine Pretreatment on the Activity, Stability and Active Sites of Cobalt Species for Preferential Oxidation (PROX) of CO in H2-Rich Stream

Transition metals cobaltites spinel for depollution of NOx emissions using SCR technology

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Transition metals cobaltites spinel for depollution of NO_x emissions using SCR technology