Nanostructured Ru-Co@SiO 2 : Highly efficient yet durable for CO 2 reforming of methane with a desirable H 2 /CO ratio

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Dry reforming of methane has been systematically investigated over a series of x‐Co@SiO2‐y catalysts where x is the Co particle size ranging from 11.1 to 121.3 nm while y denotes the silica shell thickness ranging from 6.0 to 21.9 nm. Various techniques including TEM, XRD, H2‐TPR/‐TPD, XPS, BET, O2‐TPO, TG, and H2‐TPSR‐MS were employed to characterize physicochemical properties of catalysts. H2‐TPR and XPS results indicate that the core–shell interaction is dependent on the core size: the smaller the Co particle size is; the stronger the core–shell interaction. The investigations employing H2‐TRSR‐MS and XPS on the spent catalysts demonstrated that a fraction of metallic Co was re‐oxidized on a large‐core catalyst such as 121.3‐Co@SiO2‐72.2 during the reaction, and such oxidation leads to lower catalytic activity and stability. O2‐TPO results indicated that the catalyst with smaller core size caused significant coking. TG analysis together with TEM investigation on the used samples suggested that carbon deposition is notably core‐size‐dependent and responsible for deactivation of the small‐core catalyst. Among various core–shell structured catalysts, 27.8‐Co@SiO2‐14.3 showed superior activity and durability, owing to the well‐balanced property between coking and anti‐oxidation of Co cores.

Section: Catalyst Activitysupporting

confidence: 85%

Section: Introductionmentioning

confidence: 92%

How do Core–Shell Structure Features Impact on the Activity/Stability of the Co‐based Catalyst in Dry Reforming of Methane?

Pang

Zhong

et al. 2018

Self Cite

“…They can be metal or metal oxide which can be reduced to yield M@SiO 2 core shell catalysts. For example, NiO@SiO 2 , CoO@SiO 2 , (Ni/MgAl 2 O 4 )@SiO 2 and RuO 2 −Co 3 O 4 @SiO 2 bimetallic core shell catalysts have been prepared for DRM reaction. For the former, the size of core nanoparticles can be easily tuned by adjusting the synthesis conditions such as reaction temperature and the amount of protecting ligand .…”

Section: Synthesis Methods For Core/yolk Shell Catalystsmentioning

confidence: 99%

“…This can be attributed to the poor dispersion of these core materials in solvents even with the help of surfactants and ultra‐sonicators. For instance, RuCo@SiO 2 bimetallic core shell catalysts have been synthesized using RuO 2 −Co 3 O 4 as core precursors, which were prepared via hydrothermal method and endured calcination at 500 °C for 3 h. This lead to the multi‐core shell catalysts RuO 2 −Co 3 O 4 @SiO 2 with big particle size (above 45 nm) and irregular shape …”

Section: Synthesis Methods For Core/yolk Shell Catalystsmentioning

confidence: 99%

“…RuCo@SiO 2 bimetallic core shell catalysts have been synthesized via sol‐gel method for DRM . The RuO 2 −Co 3 O 4 precursors for RuCo@SiO 2 catalysts were prepared using hydrothermal method, which resulted in uniform distribution of Ru and strong interaction with Co, thereby good synergistic effect between the bimetals.…”

Section: Applications Of Core/yolk Shell Catalysts For Hydrocarbon Rementioning

confidence: 99%

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Sintering and Coke Resistant Core/Yolk Shell Catalyst for Hydrocarbon Reforming

Wang

Kawi

2018

Syngas/hydrogen production via hydrocarbon reforming reactions is crucial. Whereas, they need high reaction temperature to obtain economically feasible hydrocarbon conversions, which renders the active and cheap transition metal based catalysts easy to be sintered, leading to the high carbon deposition rate and gradual degradation of catalytic performance. Therefore, developing sintering and carbon resistant catalysts becomes one of the most important issues for these reforming reactions to be industrially applied. Designing catalysts with core/yolk shell structure turns out to be one of the most effective strategies to solve this issue. Herein, recent progress which has been made in the synthesis method for core/yolk shell catalysts with different shell materials such as SiO2, zeolite, CeO2 and Al2O3 is summarized. Additionally, specific applications of these core/yolk catalysts for various hydrocarbon reforming reactions such as dry reforming, steam reforming and methane oxidation are reviewed with the emphasis on revealing the reasons leading to their outstanding catalytic performance. Lastly, possible research directions in core/yolk shell catalysts are proposed.

CeO₂ Nanorod@NiPhy Core‐shell Catalyst for Methane Dry Reforming: Effect of Simultaneous Sintering Prevention of CeO₂ Support and Active Ni

Liao

Chen

et al. 2022

Preventing the sintering of nano-catalyst is crucial to maintain their performance especially for high-temperature reactions such as CO 2 reforming of methane (DRM) reaction. In this paper, we design CeO 2 nanorod@Ni phyllosilicate (CeO 2 @NiPhy) catalysts with different NiPhy shell thickness to simultaneously preserve the morphology of CeO 2 nanorod and prevent the sintering of Ni. Compared with Ni/CeO 2 supported catalyst, CeO 2 @NiPhy core-shell catalyst with a shell thickness of 9 nm exhibits much better performance for DRM with stable CH 4 and CO 2 conversions of 75 % and 80 % respectively and lower carbon deposition due to high Ni sintering resistance and higher thermal stability of CeO 2 during calcination and DRM reaction thereby higher oxygen vacancies concentration. In-situ diffuse reflectance infrared Fourier transform spectra result demonstrates that DRM reaction takes place with a bi-functional mechanism on CeO 2 @NiPhy. This design strategy can be applied to prepare other nano-catalysts with high sintering resistance of both active metal and catalyst support for hightemperature applications.