Deposition Precipitation

Jong, Krijn P. de

doi:10.1002/9783527626854.ch6

Cited by 13 publications

(8 citation statements)

References 70 publications

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“…Silica-supported Ni nanoparticles were made by homogeneous deposition precipitation (HDP), and co-precipitation according to previous studies [46][47][48] . For catalysts A-G, prepared by HDP, different weight loadings (1-20%) of Ni precursor were dissolved in water, in which silica was suspended.…”

Section: Methodsmentioning

confidence: 99%

Unravelling structure sensitivity in CO2 hydrogenation over nickel

et al. 2018

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T he reduction of CO 2 emissions into the Earth's atmosphere is gaining legislative importance in view of its impact on the climate [1][2][3][4][5] . Reduction of the harmful effect of these emissions through reclamation of CO 2 is made attractive because CO 2 can be a zero-or even negative-cost carbon feedstock 6,7 . The conversion of renewably produced hydrogen and CO 2 into methane, or synthetic natural gas, over Ni is a solution that combines the potential to reduce CO 2 emissions with a direct answer to the temporal mismatch in renewable electricity production capacity and demand [8][9][10][11][12][13][14][15][16][17] . Chemical energy storage in the form of hydrogen production by electrolysis is a relatively mature technology; however, the required costly infrastructure, and inefficiencies in distribution and storage deem it inconvenient for large-scale application in the near future. Point-source CO 2 hydrogenation to methane represents an alternative approach with higher energy density. Furthermore, methane is more easily liquefied and can be stored safely in large quantities through infrastructures that already exist 18,19 . Power-to-gas (in this case methane) is thus actively considered as being capable of balancing electric grid stability, which will allow us to increase the renewable energy supply 20 .The search for fossil fuel alternatives, and application of a process such as that described above can arguably be achieved only with the help of advances in catalysis and the closely related field of nanomaterials. Continuous efforts in both fields have allowed us to make increasingly smaller and catalytically more active (metal) particles. However, it is already known that making progressively smaller supported catalyst particles does not necessarily linearly correspond to higher catalytic activity [21][22][23] . This phenomenon, where not all atoms in a supported metal catalyst have the same activity, is called structure sensitivity and is often attributed to the distinctly different chemistries on different lattice planes for π -bond activation in CO 2 , or σ -bond activation in, for example H 2 dissociation and C-H propagation 21,24 . The availability of stepped (less coordinated) versus terrace (more coordinated) sites on the surface of supported catalyst nanoparticles obviously changes with particle size, and atomic geometries become particularly interesting below 2 nm where, for example, π -bond activation is believed to not be able to occur 21 . While particle-size effects have been extensively studied for CO hydrogenation over Co 23,25 , the understanding of such structure sensitivity effects for these critical smaller metal particle sizes is lacking as sub-2-nm particles prove difficult to synthesize for first-row transition metals (Co, Fe and Ni). However, a particle-size effect for CO 2 hydrogenation is much less well established 26 .Here, we used a unique set of SiO 2 -supported Ni nanoparticles with diameters ranging from 1 to 7 nm in size, and show not only the existence of a distinct pa...

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Section: Methodsmentioning

confidence: 99%

Unravelling structure sensitivity in CO2 hydrogenation over nickel

et al. 2018

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“…The bimetallic Ni 3 Fe/Al 2 O 3 catalyst and a monometallic Ni/Al 2 O 3 reference system were both prepared via homogeneous deposition–precipitation ,, with an intended total metal loading of 20 wt %. The synthesis mixture consisted of a 0.3 mol L –1 aqueous solution of the nitrate precursors ((Ni(NO 3 ) 2 ·6 H 2 O and Fe(NO 3 ) 3 ·9 H 2 O both Merck, ≥ 99%) with n (Ni)/ n (Fe) = 3 and 7 equiv of urea (Carl Roth, crystalline, ≥99.6%).…”

Section: Methodsmentioning

confidence: 99%

Potential of an Alumina-Supported Ni₃Fe Catalyst in the Methanation of CO₂: Impact of Alloy Formation on Activity and Stability

Mutz

Belimov²,

Wu³

et al. 2017

ACS Catal.

168

105

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A promising bimetallic 17 wt % Ni3Fe catalyst supported on γ-Al2O3 was prepared via homogeneous deposition–precipitation for the application in the methanation of CO2 to gather more detailed insight into the structure and performance of the catalyst compared to state-of-the-art methanation systems. X-ray diffraction (XRD) analysis, detailed investigations using scanning transmission electron microscopy (STEM) combined with energy dispersive X-ray spectroscopy analysis (EDX) of single particles as well as larger areas, high-resolution transmission electron microscopy (HRTEM) imaging, temperature-programmed reduction (H2-TPR), and in-depth interpretation of Raman bands led to the conclusion that a high fraction of the Ni and Fe formed the desired Ni3Fe alloy resulting in small and well-defined nanoparticles with 4 nm in size and a dispersion of 24%. For comparison, a monometallic catalyst with similar dispersion using the same preparation method and analysis was prepared. Using a fixed-bed reactor, the Ni3Fe catalyst showed better low-temperature performance compared to a monometallic Ni reference catalyst, especially at elevated pressures. Long-term experiments in a microchannel packed bed reactor under industrially relevant reaction conditions in competition with a commercial Ni-based methanation catalyst revealed an improved performance of the Ni3Fe system at 358 °C and 6 bar involving enhanced conversion of CO2 to 71%, selectivity to CH4 > 98%, and most notably a high stability. Deactivation occurred only at lower temperatures, which was related to carbon deposition due to an increased CO production. Kinetic measurements were compared with literature models derived for Ni/Al2O3 catalysts, which fit well but underestimate the performance of the Ni3Fe system, emphasizing the synergetic effect of Ni and Fe.

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“…SOMC is a synthetic strategy that provides a platform for the controlled introduction of various metal components at the surface of oxide supports. ,, Typically, this has been achieved by grafting metal precursors on spatially isolated hydroxyls at the surface of a high-surface-area material through partial dehydroxylation under controlled conditions (e.g., vacuum or inert gas at a given temperature and pressure). The metal precursor, chosen among hydrocarbyls, amides, alkoxides, siloxides, etc., is grafted in organic solventpreventing the complex surface chemistry of oxide supports in water, such as dissolution/re-precipitation processes that complicate preparations by impregnation. − The selective reaction of tailored molecular precursors with these surface hydroxyls (grafting, Figure a) to yield well-defined surface species is a concept that has been exhaustively discussed in earlier reviews, which focused predominantly on their use as single-site catalysts. , …”

Section: Somc: Conceptmentioning

confidence: 99%

Deciphering Metal–Oxide and Metal–Metal Interplay via Surface Organometallic Chemistry: A Case Study with CO₂ Hydrogenation to Methanol

Docherty

Copéret

2021

J. Am. Chem. Soc.

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Processes that rely on heterogeneous catalysts underpin the production of bulk chemicals and fuels. In spite of this, understanding of the interplay between the structure and reactivity of these complex materials remains elusiverendering rational improvement of existing systems challenging. Herein, we describe efforts to understand complex materials capable of selective thermochemical conversion of CO2 to methanol using a surface organometallic chemistry (SOMC) approach. In particular, we focus on the remarkable, but often subtle, roles of metal–metal synergy and metal–support interfaces in determining the reactivity of many different systems for the conversion of CO2 to methanol. Specifically, we explore synthetic and analytical strategies for the systematic study of synergistic behaviors of multi-component catalytic systems in the context of CO2 hydrogenation, and we discuss how the insights obtained can inform the design of materials. We also address limitations of the approach employed and opportunities to expand upon the observations emerging from this work, before attempting to establish transposable and generalizable trends for Cu-based catalysts and beyond.

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Deposition Precipitation

Cited by 13 publications

References 70 publications

Unravelling structure sensitivity in CO2 hydrogenation over nickel

Unravelling structure sensitivity in CO2 hydrogenation over nickel

Potential of an Alumina-Supported Ni₃Fe Catalyst in the Methanation of CO₂: Impact of Alloy Formation on Activity and Stability

Deciphering Metal–Oxide and Metal–Metal Interplay via Surface Organometallic Chemistry: A Case Study with CO₂ Hydrogenation to Methanol

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Deposition Precipitation

Cited by 13 publications

References 70 publications

Unravelling structure sensitivity in CO2 hydrogenation over nickel

Unravelling structure sensitivity in CO2 hydrogenation over nickel

Potential of an Alumina-Supported Ni3Fe Catalyst in the Methanation of CO2: Impact of Alloy Formation on Activity and Stability

Deciphering Metal–Oxide and Metal–Metal Interplay via Surface Organometallic Chemistry: A Case Study with CO2 Hydrogenation to Methanol

Contact Info

Product

Resources

About

Potential of an Alumina-Supported Ni₃Fe Catalyst in the Methanation of CO₂: Impact of Alloy Formation on Activity and Stability

Deciphering Metal–Oxide and Metal–Metal Interplay via Surface Organometallic Chemistry: A Case Study with CO₂ Hydrogenation to Methanol