Rational Design of ZSM-5 Zeolite Containing High Concentration Single Fe Site Capable of Partial Oxidation of Methane with High Turnover Frequency

Iron-containing zeolite possesses an active site capable of low-temperature partial oxidation of methane using hydrogen peroxide as an environmentally benign oxidant. However, only a trace number of active sites has...

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Oscillatory Behaviour of Ni Supported on ZrO2 in the Catalytic Partial Oxidation of Methane as Determined by Activation Procedure

Materials ◽

10.3390/ma14102495 ◽

2021 ◽

Vol 14 (10) ◽

pp. 2495

Author(s):

Daniela Pietrogiacomi ◽

Maria Cristina Campa ◽

Ida Pettiti ◽

Simonetta Tuti ◽

Giulia Luccisano ◽

...

Keyword(s):

Catalytic Activity ◽

Partial Oxidation ◽

Active Sites ◽

Direct Reduction ◽

Partial Oxidation Of Methane ◽

Catalytic Partial Oxidation ◽

Oxidation Of Methane ◽

Short Contact Time ◽

Oxidation Reduction ◽

Ni Species

Ni/ZrO2 catalysts, active and selective for the catalytic partial oxidation of methane to syngas (CH4-CPO), were prepared by the dry impregnation of zirconium oxyhydroxide (Zhy) or monoclinic ZrO2 (Zm), calcination at 1173 K and activation by different procedures: oxidation-reduction (ox-red) or direct reduction (red). The characterization included XRD, FESEM, in situ FTIR and Raman spectroscopies, TPR, and specific surface area measurements. Catalytic activity experiments were carried out in a flow apparatus with a mixture of CH4:O2 = 2:1 in a short contact time. Compared to Zm, Zhy favoured the formation of smaller NiO particles, implying a higher number of Ni sites strongly interacting with the support. In all the activated Ni/ZrO2 catalysts, the Ni–ZrO2 interaction was strong enough to limit Ni aggregation during the catalytic runs. The catalytic activity depended on the activation procedures; the ox-red treatment yielded very active and stable catalysts, whereas the red treatment yielded catalysts with oscillating activity, ascribed to the formation of Niδ+ carbide-like species. The results suggested that Ni dispersion was not the main factor affecting the activity, and that active sites for CH4-CPO could be Ni species at the boundary of the metal particles in a specific configuration and nuclearity.

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On the nature of active sites of silica based oxide catalysts in the partial oxidation of methane to formaldehyde

Catalysis Today ◽

10.1016/0920-5861(95)00030-j ◽

1995 ◽

Vol 24 (3) ◽

pp. 231-236 ◽

Cited By ~ 16

Author(s):

A. Parmaliana ◽

F. Arena ◽

F. Frusteri ◽

D. Miceli ◽

V. Sokolovskii

Keyword(s):

Partial Oxidation ◽

Active Sites ◽

Oxide Catalysts ◽

Partial Oxidation Of Methane ◽

Oxidation Of Methane

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The Role of Active Sites Location in Partial Oxidation of Methane to Syngas for MCM-41 Supported Ni Nanoparticles

Catalysts ◽

10.3390/catal9070606 ◽

2019 ◽

Vol 9 (7) ◽

pp. 606 ◽

Cited By ~ 3

Author(s):

Chuanmin Ding ◽

Junwen Wang ◽

Yufeng Li ◽

Qian Ma ◽

Lichao Ma ◽

...

Keyword(s):

Partial Oxidation ◽

Active Sites ◽

Catalytic Performance ◽

Partial Oxidation Of Methane ◽

Pore Channel ◽

Impregnation Method ◽

Ni Nanoparticles ◽

Oxidation Of Methane ◽

Supported Ni ◽

Mcm 41

The supporting modes of active metal over mesoporous materials play an important role in catalytic performance. The location of Ni nanoparticles inside or outside the mesoporous channel of MCM-41 has a significant influence on the reactivity in partial oxidation of methane to syngas reaction. The characterization data using different techniques (Transmission Electron Microscope (TEM), X-Ray Diffraction (XRD), N2 adsorption-desorption, H2 Temperature-Programmed Reduction (H2-TPR), and Inductively Coupled Plasma (ICP)) indicated that nickel was located outside the mesoporous channels for the impregnation method (Ni/MCM-41), while nickel was encapsulated within MCM-41 via the one-step hydrothermal crystallization method (Ni-MCM-41). The nickel atoms were mainly dispersed predominantly inside the skeleton of zeolite. When the load amount of Ni increased, both of Ni species inside the skeleton or pore channel of zeolite increased, and the ordered structure of MCM-41 was destroyed gradually. Contributed by the strong interaction with MCM-41, the Ni particles of Ni-MCM-41 were highly dispersed with smaller particle size compared with supported Ni/MCM-41 catalyst. The Ni-MCM-41 displayed higher catalytic performance than Ni/MCM-41, especially 10% Ni-MCM-41 due to high dispersity of Ni. The confinement effect of MCM-41 zeolite also afforded high resistance of sintering and coking for 10% Ni-MCM-41 catalyst. Especially, 10% Ni-MCM-41 catalyst showed outstanding catalytic stability.

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