Enhanced soot combustion over partially substituted hydrotalcite-drived mixed oxide catalysts CoMgAlLaO

Dai, Fangfang; Zhang, Yuxia; Meng, Ming; Zhang, Jing; Zheng, Lirong; Hu, Tiandou

doi:10.1016/j.molcata.2014.05.031

Cited by 10 publications

(5 citation statements)

References 39 publications

(43 reference statements)

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“…Numerous catalysts for soot combustion have been reported using noble metals [7][8][9], perovskites [10,11], spinel-type oxides [12,13], hydrotalcites [14,15], alkaline metal oxides [16,17], transition metal oxides [18], and rare earth metal oxides [19]. Ag-based catalysts are promising candidates for catalytic soot oxidation reactions because of their low price among noble metals, and particularly the Ag 0 species has a high ability to activate oxygen [20][21][22].…”

Section: Introductionmentioning

confidence: 99%

Metal–Support Interactions on Ag/Co3O4 Nanowire Monolithic Catalysts Promoting Catalytic Soot Combustion

Yang

et al. 2022

Trans. Tianjin Univ.

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Tuning metal–support interactions (MSIs) is an important strategy in heterogeneous catalysis to realize the desirable metal dispersion and redox ability of metal catalysts. Herein, we use pre-reduced Co3O4 nanowires (Co-NWs) in situ grown on monolithic Ni foam substrates to support Ag catalysts (Ag/Co-NW-R) for soot combustion. The macroporous structure of Ni foam with crossed Co3O4 nanowires remarkably increases the soot–catalyst contact efficiency. Our characterization results demonstrate that Ag species exist as Ag0 because of the equation Ag+ + Co2+ = Ag0 + Co3+, and the pre-reduction treatment enhances interactions between Ag and Co3O4. The number of active oxygen species on the Ag-loaded catalysts is approximately twice that on the supports, demonstrating the significant role of Ag sites in generating active oxygen species. Additionally, the strengthened MSI on Ag/Co-NW-R further improves this number by increasing metal dispersion and the intrinsic activity determined by the turnover frequency of these oxygen species for soot oxidation compared with the catalyst without pre-reduction of Co-NW (Ag/Co-NW). In addition to high activity, Ag/Co-NW-R exhibits high catalytic stability and water resistance. The strategy used in this work might be applicable in related catalytic systems.

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Section: Introductionmentioning

confidence: 99%

Metal–Support Interactions on Ag/Co3O4 Nanowire Monolithic Catalysts Promoting Catalytic Soot Combustion

Yang

et al. 2022

Trans. Tianjin Univ.

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“…The nanofabrication of reducible CeO 2 NPs in nonreducible MgAl LDO induces high catalytic soot combustion performance because of the enhanced oxygen storage/release capabilities. , Co-based hydrotalcite-derived oxides are also active for simultaneously catalytic soot-NO x removal reactions . Adding K, Ce, and La additives can further improve their activities because of the generation of more active oxygen species. , So far, the types of active oxygen species and the essence of promotional effect on soot combustion are still unclear over Co-based hydrotalcite-derived oxides. Especially, to the best of our knowledge, few reports investigated the reaction mechanism of oxygen species over Ag catalysts interacted with hydrotalcite-derived metal oxides for soot combustion.…”

Section: Introductionmentioning

confidence: 99%

“…25 Adding K, Ce, and La additives can further improve their activities because of the generation of more active oxygen species. 26,27 So far, the types of active oxygen species and the essence of promotional effect on soot combustion are still unclear over Co-based hydrotalcite-derived oxides. Especially, to the best of our knowledge, few reports investigated the reaction mechanism of oxygen species over Ag catalysts interacted with hydrotalcite-derived metal oxides for soot combustion.…”

Section: ■ Introductionmentioning

confidence: 99%

Identifying Oxygen Activation/Oxidation Sites for Efficient Soot Combustion over Silver Catalysts Interacted with Nanoflower-Like Hydrotalcite-Derived CoAlO Metal Oxides

et al. 2019

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Catalytic oxidation is an effective way to eliminate soot pollution emitted from diesel engines. However, the origination and specific location of active oxygen species are still unclear over noble metal catalysts because of the complex gas (oxygen)–solid (catalyst)–solid (reactant) reaction systems. Herein, we report the high catalytic performance of the nanoflower-like hydrotalcite-derived CoAlO-supported Ag catalyst synthesized by a facile hydrothermal method for soot combustion. Our characterization results demonstrate that metallic Ag nanoparticles (NPs) are highly dispersed on the CoAlO support because of their interactions through electron donation from Co to Ag species. The isotopic 18O2 adsorption/desorption results reveal that gaseous oxygen is readily adsorbed and dissociated on these electron-enriched Ag NPs rather than oxygen vacancies of the CoAlO support. From the 18O2 isothermal soot oxidation results, we newly discover that surface oxygen species adsorbed on Ag sites directly participate in soot oxidation, while those on the CoAlO support only play a negligible role. The kinetic results show that the strengthened Ag–CoAlO interactions can promote not only the quantity but also the intrinsic activity of oxygen species on Ag sites for soot combustion. In addition, the nanoflower-like morphology of the catalyst can greatly improve the soot–catalyst contact efficiency to further enhance the catalytic performance. Our work brings an insight into the identification of oxygen activation/oxidation sites involved in soot oxidation over Ag catalysts supported on hydrotalcite-derived CoAlO metal oxides by systematic isotopic and kinetic investigations, which is beneficial to the rational design of other related catalytic systems.

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“…Therefore, the focus in the CRT system for soot elimination is to develop effective catalysts, which can oxidize soot within the temperature range (250–400 °C) of diesel engine exhaust. A large number of catalysts for soot combustion have been reported, such as noble metals, , perovskites, − spinel-type oxides, , hydrotalcites, , alkaline metal oxides, , ceria-based oxides, − and transition metal oxides. − Recently, Fang et al synthesized the perovskite-type La 1– x K x FeO 3‑δ nanotubes, which showed high material utilization efficiency and improved catalytic soot oxidation activity. Hernández et al reported an Ag-modified LaSrAgMn perovskite with promising catalytic soot oxidation performance under low O 2 partial pressure.…”

Section: Introductionmentioning

confidence: 99%

Decorating CeO₂ Nanoparticles on Mn₂O₃ Nanosheets to Improve Catalytic Soot Combustion

Xing

Yang

Cao

et al. 2018

ACS Sustainable Chem. Eng.

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Herein, we synthesized CeO2 nanoparticles-decorated Mn2O3 nanosheets on monolithic Ni foam (Ce/Mn-NF) for catalytic elimination of soot particulates. The macroporous nanostructures created by the Mn2O3 nanosheets improve the soot-catalyst contact efficiency on the external surface of catalysts. The superficial Mn–Ce interaction can produce Mn4+ and oxygen vacancies on the Ce/Mn-NF catalysts through the redox process of Ce4+ + Mn3+ ↔ Mn4+ + Ce3+, simultaneously generating surface active oxygen species. Moreover, our results demonstrate that the surface adsorbed oxygen species induced by the Mn–Ce interaction are more active for catalytic soot oxidation than those on the Mn-NF. Thus, the introduction of the CeO2 nanoparticles to the Mn2O3 nanosheets can significantly improve the catalytic activity for soot combustion. For the Ce/Mn-NF-2, the surface atomic ratio of Ce and Mn is close to 1:1, which will create more Mn–Ce interaction sites to generate active oxygen species compared with other catalysts. Accordingly, it exhibits higher catalytic activity. The tactful design of the MnO x –CeO2 catalysts successfully overcomes the problems of how to construct macroporous nanostructures with mixed metal oxides, and this strategy of material design may be applied in other related catalytic systems.

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Enhanced soot combustion over partially substituted hydrotalcite-drived mixed oxide catalysts CoMgAlLaO

Cited by 10 publications

References 39 publications

Metal–Support Interactions on Ag/Co3O4 Nanowire Monolithic Catalysts Promoting Catalytic Soot Combustion

Metal–Support Interactions on Ag/Co3O4 Nanowire Monolithic Catalysts Promoting Catalytic Soot Combustion

Identifying Oxygen Activation/Oxidation Sites for Efficient Soot Combustion over Silver Catalysts Interacted with Nanoflower-Like Hydrotalcite-Derived CoAlO Metal Oxides

Decorating CeO₂ Nanoparticles on Mn₂O₃ Nanosheets to Improve Catalytic Soot Combustion

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Enhanced soot combustion over partially substituted hydrotalcite-drived mixed oxide catalysts CoMgAlLaO

Cited by 10 publications

References 39 publications

Metal–Support Interactions on Ag/Co3O4 Nanowire Monolithic Catalysts Promoting Catalytic Soot Combustion

Metal–Support Interactions on Ag/Co3O4 Nanowire Monolithic Catalysts Promoting Catalytic Soot Combustion

Identifying Oxygen Activation/Oxidation Sites for Efficient Soot Combustion over Silver Catalysts Interacted with Nanoflower-Like Hydrotalcite-Derived CoAlO Metal Oxides

Decorating CeO2 Nanoparticles on Mn2O3 Nanosheets to Improve Catalytic Soot Combustion

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Decorating CeO₂ Nanoparticles on Mn₂O₃ Nanosheets to Improve Catalytic Soot Combustion