Surfactant-free synthesis of sub-10 nm Co3O4 in a rotating packed bed and its high catalytic activity for AP pyrolysis

In this work, low-Pt content nanocatalysts (≈ 5 wt. %) supported on Hollow Carbon Spheres (HCS) were synthesized by two routes: i) colloidal conventional polyol, and ii) surfactant-free Bromide Anion Exchange (BAE). The nanocatalysts were labelled as Pt/HCS-P and Pt/HCS-B for polyol and BAE, respectively. The physicochemical characterization of the nanocatalysts showed that by following both methods, a good control of chemical composition was achieved, obtaining in addition well dispersed nanoparticles of less than 3 nm TEM average particle size (d) on the HCS. Pt/HCS-B contained more Pt0 species than Pt/HCS-P, an effect of the synthesis method. In addition, the structure of the HCS remains more ordered after BAE synthesis, compared to polyol. Regarding the catalytic activity for the Oxygen Reduction Reaction (ORR) in 0.5 M KOH, Pt/HCS-P and Pt/HCS-B showed a similar performance in terms of current density (j) at 0.9 V vs. RHE than the benchmark commercial 20 wt. % Pt/C. However, Pt/HCS-P and Pt/HCS-B demonstrated a 6 and 5-fold increase in mass catalytic activity compared to Pt/C, respectively. A positive effect of the high specific surface area of the HCS and its interactions with metal nanoparticles and electrolyte, which promoted the mass transfer, increased the performance of Pt/HCS-P and Pt/HCS-B. The high catalytic activity showed by Pt/HCS-B and Pt/HCS-P for the ORR, even with a low-Pt content, make them promising cathode nanocatalysts for Anion Exchange Membrane Fuel Cells (AEMFC).

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Ordered Intermetallic Nanoparticles with High Catalytic Activity Prepared by an Electrochemically Induced Phase Transformation

10.26434/chemrxiv.8289812 ◽

2019 ◽

Author(s):

Du Sun ◽

yunfei wang ◽

Kenneth Livi ◽

chuhong wang ◽

ruichun luo ◽

...

Keyword(s):

Catalytic Activity ◽

Diffusion Mechanism ◽

Reduction Reaction ◽

Atomic Scale ◽

High Catalytic Activity ◽

Ambient Conditions ◽

Magnetic Devices ◽

Disordered Alloys ◽

Ordered Intermetallic ◽

Intermetallic Nanoparticles

<div> The synthesis of alloys with long range atomic scale ordering (ordered intermetallics) is an emerging field of nanochemistry. Ordered intermetallic nanoparticles are useful for a wide variety of applications such as catalysis, superconductors, and magnetic devices. However, the preparation of nanostructured ordered intermetallics is challenging in comparison to disordered alloys, hindering progress in materials development. We report a process for converting colloidally synthesized ordered intermetallic PdBi2 to ordered intermetallic Pd3Bi nanoparticles under ambient conditions by an electrochemically induced phase transition. The low melting point of PdBi2 corresponds to low vacancy formation energies which enables the facile removal of the Bi from the surface, while simultaneously enabling interdiffusion of the constituent atoms via a vacancy diffusion mechanism under ambient conditions. The resulting phase-converted ordered intermetallic Pd3Bi exhibits 11x and 3.5x higher mass activty and high methanol tolerance for the oxygen reduction reaction compared to Pt/C and Pd/C, respectively,which is the highest reported for a Pd-based catalyst, to the best of our knowledge. These results establish a key development in the synthesis of noble metal rich ordered intermetallic phases with high catalytic activity, and sets forth guidelines for the design of ordered intermetallic compounds under ambient conditions. </div>

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Comparative Study of CO2 Capture Using Counter and Cross Flow Configurations in a Rotating Packed Bed Absorber Using Mono Ethanol Amine (MEA)

SSRN Electronic Journal ◽

10.2139/ssrn.3366018 ◽

2019 ◽

Author(s):

Toluwanimi Kolawole ◽

Pierrot Attidekou ◽

James Hendry ◽

Jonathan Lee

Keyword(s):

Comparative Study ◽

Co2 Capture ◽

Cross Flow ◽

Packed Bed ◽

Rotating Packed Bed ◽

Flow Configurations

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Nickel (II) and oxovanadium (IV) complexes supported on MCM-41 mesoporous and their application in catalytic selective sulfide and thiol oxidation

Combinatorial Chemistry & High Throughput Screening ◽

10.2174/1386207323999201111192649 ◽

2020 ◽

Vol 23 ◽

Author(s):

Mohsen Nikoorazm ◽

Maryam Khanmoradi ◽

Masoumeh Sayadian

Keyword(s):

Catalytic Activity ◽

Room Temperature ◽

Sol Gel ◽

Reaction Times ◽

Significant Loss ◽

Spectral Studies ◽

High Catalytic Activity ◽

Catalytic Systems ◽

Solvent Free Conditions ◽

Mcm 41

Introduction:: MCM-41 was synthesized using the sol-gel method. Then two new transition metal complexes of Nickel (II) and Vanadium (IV), were synthesized by immobilization of adenine (6-aminopurine) into MCM-41 mesoporous. The compounds have been characterized by XRD, TGA, SEM, AAS and FT-IR spectral studies. Using these catalysts provided an efficient and enantioselective procedure for oxidation of sulfides to sulfoxides and oxidative coupling of thiols to their corresponding disulfides using hydrogen peroxide at room temperature. Materials and Methods:: To a solution of sulfide or thiol (1 mmol) and H2O2 (5 mmol), a determined amount of the catalyst was added. The reaction mixture was stirred at room temperature for the specific time under solvent free conditions. The progress of the reaction was monitored by TLC using n-hexane: acetone (8:2). Afterwards, the catalyst was removed from the reaction mixture by centrifugation and, then, washed with dichloromethane in order to give the pure products. Results:: All the products were obtained in excellent yields and short reaction times indicating the high activity of the synthesized catalysts. Besides, the catalysts can be recovered and reused for several runs without significant loss in their catalytic activity. Conclusion:: These catalytic systems furnish the products very quickly with excellent yields and VO-6AP-MCM-41 shows high catalytic activity compared to Ni-6AP-MCM-41.

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Intensification of CO₂ capture by monoethanolamine solution containing TiO2 nanoparticles in a rotating packed bed

International Journal of Greenhouse Gas Control ◽

10.1016/j.ijggc.2019.102933 ◽

2020 ◽

Vol 94 ◽

pp. 102933 ◽

Cited By ~ 1

Author(s):

Masoud Shirzadi Ahou Dashti ◽

Mahdieh Abolhasani

Keyword(s):

Tio2 Nanoparticles ◽

Packed Bed ◽

Rotating Packed Bed

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Mechanisms of methane decomposition and carbon species oxidation on the Pr0.42Sr0.6Co0.2Fe0.7Nb0.1O3−σ electrode with high catalytic activity

Journal of Materials Chemistry A ◽

10.1039/c5ta07599h ◽

2015 ◽

Vol 3 (45) ◽

pp. 22816-22823 ◽

Cited By ~ 5

Author(s):

Peng Zhang ◽

Guoqing Guan ◽

Deni S. Khaerudini ◽

Xiaogang Hao ◽

Chunfeng Xue ◽

...

Keyword(s):

Catalytic Activity ◽

Carbon Deposition ◽

Methane Decomposition ◽

High Catalytic Activity ◽

Carbon Species

Carbon deposition characteristics on PSCFN and Ni–YSZ due to thermal CH4 decomposition are investigated by using TPR technique.

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Bio-Derived Catalysts: A Current Trend of Catalysts Used in Biodiesel Production

Catalysts ◽

10.3390/catal11070812 ◽

2021 ◽

Vol 11 (7) ◽

pp. 812

Author(s):

Hoang Chinh Nguyen ◽

My-Linh Nguyen ◽

Chia-Hung Su ◽

Hwai Chyuan Ong ◽

Horng-Yi Juan ◽

...

Keyword(s):

Catalytic Activity ◽

Fossil Fuels ◽

Current Trend ◽

Biodiesel Production ◽

High Catalytic Activity ◽

Promising Alternative ◽

Advantages And Disadvantages ◽

Biodiesel Synthesis ◽

Alkali Catalysts ◽

A Current

Biodiesel is a promising alternative to fossil fuels and mainly produced from oils/fat through the (trans)esterification process. To enhance the reaction efficiency and simplify the production process, various catalysts have been introduced for biodiesel synthesis. Recently, the use of bio-derived catalysts has attracted more interest due to their high catalytic activity and ecofriendly properties. These catalysts include alkali catalysts, acid catalysts, and enzymes (biocatalysts), which are (bio)synthesized from various natural sources. This review summarizes the latest findings on these bio-derived catalysts, as well as their source and catalytic activity. The advantages and disadvantages of these catalysts are also discussed. These bio-based catalysts show a promising future and can be further used as a renewable catalyst for sustainable biodiesel production.

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