Atomically dispersed nickel as coke-resistant active sites for methane dry reforming

Akri, Mohcin; Zhao, Shu; Li, Xiaoyü; Zang, Ketao; Lee, Adam F.; Isaacs, Mark A.; Xi, Wei; Gangarajula, Yuvaraj; Luo, Jun; Ren, Yujing; Cui, Yi‐Tao; Li, Lei; Su, Yang; Pan, Xiaoli; Wen, Wu; Pan, Yang; Wilson, Karen; Li, Lin; Qiao, Botao; Ishii, Hirofumi; Liao, Yen Fa; Wang, Aiqin; Wang, Xiaodong; Zhang, Tao

doi:10.1038/s41467-019-12843-w

Cited by 489 publications

(334 citation statements)

References 60 publications

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“…Intriguingly, NiHAP(0) contains lower coordination number at 5.872, as compared to NiHAP(0.5) and NiHAP(2.0) which is consistent with the nanoparticle size as reported in Table 1.The presence of lower coordination number on NiHAP(0) may be due to the presence of Ni clusters on the HAP surface [22] …”

Section: Resultssupporting

confidence: 82%

“…Akri et al. had reported on the presence of Ni 0 clusters, single atoms and nanoparticles on the nickel on Ce‐doped HAP catalyst [22] . The Ni 0 single atoms and/or clusters can be responsible for CO formation while the Ni 0 nanoparticles may be responsible for CH 4 formation which may explain for higher CO selectivity as compared to NiHAP(0.5) and NiHAP(2.0) [35,37] .…”

Section: Resultsmentioning

confidence: 99%

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Influence of Surface Formate Species on Methane Selectivity for Carbon Dioxide Methanation over Nickel Hydroxyapatite Catalyst

et al. 2020

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Absence of mechanistic understanding of carbon dioxide (CO2) methanation reaction on nickel hydroxyapatite (NiHAP) and the nature of nickel chemical state hampers the enhancement of catalytic activity and selectivity for such material. A varying amount of oleic acid (OA) addition on NiHAP is found to have a strong influence on the chemical state of nickel as evidenced from x‐ray spectroscopy (XPS) and x‐ray absorption spectroscopy (XAS). The chemical state of nickel influences the amount of surface intermediate species which affects methane formation as observed in infra‐red spectroscopy. This suggests that varying amount of OA can influence the chemical state of nickel which is important in influencing the type of reaction intermediates on the NiHAP surface. Langmuir‐Hinshelwood model is validated for proposed reaction mechanism for the better performing catalyst. The findings reported here is useful for designing a hydroxyapatite‐based catalyst for CO2 utilization.

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Section: Resultssupporting

confidence: 82%

Section: Resultsmentioning

confidence: 99%

Influence of Surface Formate Species on Methane Selectivity for Carbon Dioxide Methanation over Nickel Hydroxyapatite Catalyst

et al. 2020

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“…Nickel supported on CeO2 is an important catalyst material with promise in a wide variety of applications, [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17] perhaps most importantly in the direct conversion of methane to methanol. 14 Ceria is a widely-used support material for late transition metal catalysts, [18][19][20] and is well known to enhance the stability of supported metals to resist deactivation by sintering.…”

Section: Introductionmentioning

confidence: 99%

Ni Nanoparticles on CeO₂(111): Energetics, Electron Transfer, and Structure by Ni Adsorption Calorimetry, Spectroscopies, and Density Functional Theory

et al. 2020

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The morphology, interfacial bonding energetics and charge transfer of Ni clusters and nanoparticles on slightly-reduced CeO2-x(111) surfaces at 100 to 300 K have been studied using single crystal adsorption calorimetry (SCAC), low-energy ion scattering spectroscopy (LEIS), Xray photoelectron spectroscopy (XPS), low energy electron diffraction (LEED) and density functional theory (DFT). The initial heat of adsorption of Ni vapor decreased with the extent of pre-reduction (x) of the CeO2-x(111), showing that stoichiometric ceria adsorbs Ni more strongly than oxygen vacancies. On CeO1.95(111) at 300 K, the heat dropped quickly with coverage in the first 0.1 ML, attributed to nucleation of Ni clusters on stoichiometric steps, followed by the Ni particles spreading onto less favorable terrace sites. At 100 K, the clusters nucleate on terraces due to slower diffusion. Adsorbed Ni monomers are in the +2 oxidation state, and they bind by ~45 kJ/mol more strongly to step sites than terraces. The measured heat of adsorption versus average particle size on terraces is favorably compared to DFT calculations. The Ce 3d XPS lineshape showed an increase in Ce 3+ /Ce 4+ ratio with Ni coverage, providing the number of electrons donated to the ceria per Ni atom. The charge transferred per Ni is initially large but strongly decreases with increasing cluster size for both experiments and DFT, and shows large differences between clusters at steps versus terraces. This charge is localized on the interfacial Ni and Ce atoms in their atomic layers closest to the interface. This knowledge is crucial to understanding the nature of the active sites on the surface of Ni-CeO2 catalysts for which metal-oxide interactions play a very important role in the activation of O−H and C−H bonds. The changes in these interactions with Ni particle size (metal loading) and the extent of reduction of the ceria help to explain how previously reported catalytic activity and selectivity change with these same structural details.

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“…Within the catalysts, Ni depicted the greatest performance due to its strong ability to break C-C/C-H bonds and activate CH 4 [20]. AKri et al [21] elaborated the dry reforming of CH 4 employing atomically dispersed Ni atoms, stabilized by interaction with Ce-doped hydroxyapatite. Their results evidenced that the catalyst was very active and that isolated Ni atoms were inherently coke resistant.…”

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confidence: 99%

Dry Reforming of Methane Using Ce-modified Ni Supported on 8%PO4 + ZrO2 Catalysts

et al. 2020

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Dry reforming of methane (DRM) was studied in the light of Ni supported on 8%PO 4 + ZrO 2 catalysts. Cerium was used to modify the Ni active metal. Different percentage loadings of Ce (1%, 1.5%, 2%, 2.5%, 3%, and 5%) were tested. The wet incipient impregnation method was used for the preparation of all catalysts. The catalysts were activated at 700 • C for 1 2 h. The reactions were performed at 800 • C using a gas hourly space velocity of 28,000 mL (h·gcat) −1 . X-ray diffraction (XRD), N 2 physisorption, hydrogen temperature programmed reduction (H 2 -TPR), temperature programmed oxidation (TPO), temperature programmed desorption (TPD), and thermogravimetric analysis (TGA) were used for characterizing the catalysts. The TGA analysis depicted minor amounts of carbon deposition. The CO 2 -TPD results showed that Ce enhanced the basicity of the catalysts. The 3% Ce loading possessed the highest surface area, the largest pore volume, and the greatest pore diameter. All the promoted catalysts enhanced the conversions of CH 4 and CO 2 . Among the promoted catalysts tested, the 10Ni + 3%Ce/8%PO 4 + ZrO 2 catalyst system operated at 1 bar and at 800 • C gave the highest conversions of CH 4 (95%) and CO 2 (96%). The stability profile of Cerium-modified catalysts (10%Ni/8%PO 4 + ZrO 2 ) depicted steady CH 4 and CO 2 conversions during the 7.5 h time on stream.Catalysts 2020, 10, 242 2 of 16 the dry reforming of CH 4 . They tested the catalytic activity over La 0.4 M 0.6 Al 0.2 Ni 0.8 O 3 (M = Pt, Pd, Ru, Rh, Ir) perovskite-type oxides with a surface area of 3.26-4.14 m 2 /g. It was obtained that the La 0.4 Rh 0.6 Al 0.2 Ni 0.8 O 3 catalyst revealed the best catalytic performance due to its high surface area, surface oxygen concentration, and good low-temperature reducibility. El Hassan et al. [18] studied the influence of Rh (0.2 and 0.5 wt %) to the Co/SBA-15 catalyst in the catalytic performance of dry reforming of CH 4 . It was found that Rh favored Co stabilization in the mesopores and was reduced at a much lower temperature. The nature of coke was affected and less γ-carbon formed on the Rh-containing sample. However, because of the high prices and limited availability of noble metals, the research has also focused on transition metals such as Co, Ni, Ti, which are broadly used for this process because of their high activity [19]. However, these catalysts are prone to quick deactivation due to coke deposition. Within the catalysts, Ni depicted the greatest performance due to its strong ability to break C-C/C-H bonds and activate CH 4 [20]. AKri et al. [21] elaborated the dry reforming of CH 4 employing atomically dispersed Ni atoms, stabilized by interaction with Ce-doped hydroxyapatite. Their results evidenced that the catalyst was very active and that isolated Ni atoms were inherently coke resistant. Ce doping of hydroxyapatite brought strong metal-support interactions which stabilized Ni single atoms toward sintering and favored the selective activation of only the first C-H bond in CH 4 . Goula et al. [22] inves...

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Atomically dispersed nickel as coke-resistant active sites for methane dry reforming

Cited by 489 publications

References 60 publications

Influence of Surface Formate Species on Methane Selectivity for Carbon Dioxide Methanation over Nickel Hydroxyapatite Catalyst

Influence of Surface Formate Species on Methane Selectivity for Carbon Dioxide Methanation over Nickel Hydroxyapatite Catalyst

Ni Nanoparticles on CeO₂(111): Energetics, Electron Transfer, and Structure by Ni Adsorption Calorimetry, Spectroscopies, and Density Functional Theory

Dry Reforming of Methane Using Ce-modified Ni Supported on 8%PO4 + ZrO2 Catalysts

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Atomically dispersed nickel as coke-resistant active sites for methane dry reforming

Cited by 489 publications

References 60 publications

Influence of Surface Formate Species on Methane Selectivity for Carbon Dioxide Methanation over Nickel Hydroxyapatite Catalyst

Influence of Surface Formate Species on Methane Selectivity for Carbon Dioxide Methanation over Nickel Hydroxyapatite Catalyst

Ni Nanoparticles on CeO2(111): Energetics, Electron Transfer, and Structure by Ni Adsorption Calorimetry, Spectroscopies, and Density Functional Theory

Dry Reforming of Methane Using Ce-modified Ni Supported on 8%PO4 + ZrO2 Catalysts

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Ni Nanoparticles on CeO₂(111): Energetics, Electron Transfer, and Structure by Ni Adsorption Calorimetry, Spectroscopies, and Density Functional Theory