Highly active Pd catalysts supported on surface-modified cobalt-nickel mixed oxides for low temperature oxidation of lean methane

Li, Cunshuo; Li, Wenzhi; Ogunbiyi, Ajibola T.; Zhou, Zean; Duan, Qiuyan; Xue, Fengyang

doi:10.1016/j.fuel.2020.118372

Cited by 32 publications

(24 citation statements)

References 53 publications

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“…22 The peaks at a binding energy of ∼533.0 eV corresponded to the surface hydroxyl (O OH ) species. 27 The quantitative results of the O 1s spectra are shown in Tables 2 and S2. The peak located at 533.0 eV occupied an important part (0.23) in the spectrum of NiO-NSL, whereas the content of the hydroxyl groups on the other samples was negligible.…”

Section: Activity Determination and Specific Reactionmentioning

confidence: 99%

Irregularly Shaped NiO Nanostructures for Catalytic Lean Methane Combustion

Ogunbiyi

et al. 2021

ACS Appl. Nano Mater.

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NiO nanomaterials prepared using a solid−liquid NH 3 • H 2 O precipitation method (NiO-NSL) were tested in the catalytic combustion of methane. The NiO-NSL presented a characteristic rodlike nanostructure with a length of about a few hundred nanometers except for a part of the nanoparticles. For comparison, the NiO nanomaterials prepared by the traditional liquid-phase NH 3 •H 2 O precipitation method (NiO-NLL) were tested in the same reaction conditions. NiO-NSL exhibited significantly higher methane combustion activity than NiO-NLL and achieved the complete combustion of methane at 390 °C, which was outstanding in non-noble metal-based catalyst. X-ray photoelectron spectroscopy (XPS) and hydrogentemperature-programmed reduction (H 2 -TPR) results indicate that the surface Ni 2+ content of NiO-NSL was higher than that of NiO-NLL, and the presence of more Ni 2+ might be responsible for the enhanced activity. DFT calculations prove that the energy barrier for C−H bond activation on Ni 2+ was lower than that on Ni 3+ , which was consistent with the higher methane catalytic combustion activity of NiO-NSL. In addition, when the precipitating agent was replaced with NaOH and (NH 4 ) 2 CO 3 , the generalization of the solid−liquid precipitation method in the preparation of the NiO catalysts was also tested. The results show that the solid−liquid precipitation method proposed in this work was still applicable when NaOH was used as a precipitant. However, with the use of (NH 4 ) 2 CO 3 as a precipitant, the methane catalytic activity of the NiO nanoparticles prepared by the solid−liquid precipitation method was reduced to a certain extent compared with the traditional liquid-phase precipitation method. This research can open up a highly efficient and environmentally friendly method for the synthesis of methane combustion catalysts.

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Section: Activity Determination and Specific Reactionmentioning

confidence: 99%

Irregularly Shaped NiO Nanostructures for Catalytic Lean Methane Combustion

Ogunbiyi

et al. 2021

ACS Appl. Nano Mater.

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“…Consequently, O 2 -TPD experiments (Figure S3B) were conducted to understand the oxygen activities of HfO 2 -related samples inspired by the discussion of H 2 -TPR results. In general, the desorption of surface-adsorbed oxygen occurs at temperatures below 400 °C, 43 identical to the temperature window of the methane combustion reaction, and lattice oxygen would release from the bulk domain of catalyst materials at higher temperatures. The more intensive liberation of O ads species in 1.0Pd/HfO 2 and 1.0Pd/mod-HfO 2 compared to their HfO 2 and mod-HfO 2 supports, which was in agreement with the conclusion drawn from O 1s XPS spectra, confirmed that the deposition of palladium could enhance the activation of oxygen species.…”

Section: Resultsmentioning

confidence: 99%

Palladium Nanoparticles Supported on Surface-Modified Metal Oxides for Catalytic Oxidation of Lean Methane

Ogunbiyi

et al. 2020

ACS Appl. Nano Mater.

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Palladium nanoparticles (NPs) were successfully deposited on surface-modified metal oxides (mod-MO x , M = Hf, Ti, Zr, Ce, and Al) and applied as catalyst materials for lean methane combustion. It was found that the surface modification of support materials improved the light-off performance of 1.0Pd/mod-HfO2 (palladium catalyst supported on surface-modified HfO2 with a content of 1.0 wt %), 1.0Pd/mod-ZrO2, and 1.0Pd/mod-CeO2, but lowered the purification efficiency of 1.0Pd/mod-TiO2 and 1.0Pd/mod-Al2O3 when compared with their 1.0Pd/MOx counterparts. Over the best-performing 1.0Pd/mod-HfO2 material, 90% of methane was removed at 317 °C and a space velocity of 60 000 mL g–1 h–1, which was 120 °C lower than that required for the untreated 1.0Pd/HfO2 sample. Detailed characterization of representative HfO2-related materials showed that the introduced silicon modifier materials, which existed as an amorphous phase covering the HfO2 surface, could improve the dispersion of palladium nanoparticles due to their steric confinement and strengthen the generation of surface-adsorbed oxygen species via electron transfer. We believe that this surface modification strategy, which could promote the catalytic performance of palladium nanoparticles supported on other cost-effective host materials as well, provides a feasible method for the design of methane combustion catalysts with excellent low-temperature performance.

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“…29,30 This is often accomplished by tuning the optimal amount of Pd x+ surface species (0≤x≤4) which are stabilized on the surface and subsurface region based on reaction conditions, surface dopants and support type. [31][32][33][34] We previously reported a novel solvent-free mechano-chemical route for the synthesis of highly active methane oxidation Pd/CeO2 catalysts starting from either metallic Pd nanopowders or Pd salts. 35,36 The developed synthesis procedure resulted in catalytic materials with a peculiar coreshell morphology, displaying enhanced methane oxidation activity at low and high temperature and improved stability in the presence of excess steam.…”

Section: Introductionmentioning

confidence: 99%

“…Currently, it accounts for the major contribution to CH 4 release in optimized aftertreatment systems since the stable nature of the CH 4 molecule (C–H bond energy = 439 kJ/mol) hinders its low temperature abatement . Several approaches have been considered to reduce its ignition delay, including innovative design of the reactor setup for faster heating and optimization of the Pd active phase for CH 4 activation at lower temperature. , This is often accomplished by tuning the optimal amount of Pd x + surface species (0 ≤ x ≤ 4) which are stabilized on the surface and subsurface region based on reaction conditions, surface dopants, and support type. − …”

Section: Introductionmentioning

confidence: 99%

Pd/CeO₂ Catalysts Prepared by Solvent-free Mechanochemical Route for Methane Abatement in Natural Gas Fueled Vehicles

Danielis

Colussi

Llorca

et al. 2021

Ind. Eng. Chem. Res.

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The increasing diffusion of alternative mobility solutions, ranging from electric technologies to natural gas fueled vehicles (NGVs), has led to a progressive life-cycle analysis approach of their environmental impact in terms of greenhouse gases (GHGs) emissions. This new approach prompted a careful design of the NGVs catalytic aftertreatment system in order to minimize the catalytic converter carbon footprint as well as the unburned methane emissions at tailpipe. Here, a series of Pd/CeO2 methane oxidation catalysts were prepared by an environmentally friendly solvent-free method and compared to the commercial wet-synthesized state-of-the-art catalysts. Their application in NGVs aftertreatment systems was evaluated by testing powder catalysts and coated monolith cores for CH4 oxidation and steam reforming, which are the main methane abatement reactions occurring in a three-way catalyst (TWC) under lean and rich conditions, respectively. Pd/CeO2 catalysts prepared by mechanochemical synthesis initially displayed superior activity compared to their counterpart obtained by conventional wet impregnation, especially under lean oxidation conditions, but appeared less resistant to the industrial aging process after core washcoating. Lambda sweep experiments carried out under full gas composition proved that, despite needing further optimization in the washcoating and aging processes, the developed mild milling synthesis procedure is a viable way for the production of Pd/CeO2 based catalysts for natural gas TWCs.

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Highly active Pd catalysts supported on surface-modified cobalt-nickel mixed oxides for low temperature oxidation of lean methane

Cited by 32 publications

References 53 publications

Irregularly Shaped NiO Nanostructures for Catalytic Lean Methane Combustion

Irregularly Shaped NiO Nanostructures for Catalytic Lean Methane Combustion

Palladium Nanoparticles Supported on Surface-Modified Metal Oxides for Catalytic Oxidation of Lean Methane

Pd/CeO₂ Catalysts Prepared by Solvent-free Mechanochemical Route for Methane Abatement in Natural Gas Fueled Vehicles

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Highly active Pd catalysts supported on surface-modified cobalt-nickel mixed oxides for low temperature oxidation of lean methane

Cited by 32 publications

References 53 publications

Irregularly Shaped NiO Nanostructures for Catalytic Lean Methane Combustion

Irregularly Shaped NiO Nanostructures for Catalytic Lean Methane Combustion

Palladium Nanoparticles Supported on Surface-Modified Metal Oxides for Catalytic Oxidation of Lean Methane

Pd/CeO2 Catalysts Prepared by Solvent-free Mechanochemical Route for Methane Abatement in Natural Gas Fueled Vehicles

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Pd/CeO₂ Catalysts Prepared by Solvent-free Mechanochemical Route for Methane Abatement in Natural Gas Fueled Vehicles