Catalytic Activity of Ni Nanotubes Covered with Nanostructured Gold

Ni nanotubes (NTs) were produced by the template method in the pores of ion-track membranes and then were successfully functionalized with gold nanoparticles (Ni@Au NTs) using electroless wet-chemical deposition with the aim to demonstrate their high catalytic activity. The fabricated NTs were characterized using a variety of techniques in order to determine their morphology and dimensions, crystalline structure, and magnetic properties. The morphology of Au coating depended on the concentration of gold chloride aqueous solution used for Au deposition. The catalytic activity was evaluated by a model reaction of the reduction of 4-nitrophenol by borohydride ions in the presence of Ni and Ni@Au NTs. The reaction was monitored spectrophotometrically in real time by detecting the decrease in the absorption peaks. It was found that gold coating with needle-like structure formed at a higher Au-ions concentration had the strongest catalytic effect, while bare Ni NTs had little effect. The presence of a magnetic core allowed the extraction of the catalyst with the help of a magnetic field for reusable applications.

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Designing Ru-doped Zn3V3O8 bifunctional OER and HER catalysts through a unified computational and experimental approach

Nanoscale ◽

10.1039/d1nr04978j ◽

2021 ◽

Author(s):

Xuyan Zhou ◽

Xiaowei Tang ◽

Haitao Xu ◽

Tao Jiang ◽

Kailong Hu ◽

...

Keyword(s):

Catalytic Activity ◽

Experimental Approach ◽

Catalytic Effect ◽

High Catalytic Activity ◽

Precise Control ◽

Ru Doping

Precise control of Ru doping sites on Zn3V3O8 induces high catalytic activity. Specifically, the Ru-doped B-layer by replacing surface V shows the best OER catalytic effect, while the HER favors the Ru-doped D-layer by replacing surface Zn8.

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Über den Einfluß äußerer Magnetfelder auf die Aktivität ferromagnetischer Katalysatoren

Zeitschrift für Naturforschung A ◽

10.1515/zna-1953-0904 ◽

1953 ◽

Vol 8 (9) ◽

pp. 538-546 ◽

Cited By ~ 1

Author(s):

E. Justi ◽

G. Vieth

Keyword(s):

Catalytic Activity ◽

Nickel Powder ◽

Catalytic Effect ◽

Theoretical Treatment ◽

High Catalytic Activity ◽

Experimental Proof ◽

Apparent Lack ◽

Low Field ◽

Order Of Magnitude ◽

Catalytic Effects

J.A. Hedvall has discovered “internal” magneto-catalytic effects; the activity of ferromagnetic catalyst changes upon transgressing the Curie-interval. The present publication deals with finding an “external” magneto-catalytic effect consisting of the influence of external magnetic fields upon the activity of ferromagnetic catalysts. This can be shown quite clearly in capillaries of high purity ferromagnetic nickel by experiments applying the o-p-hydrogen conversion. In this reaction the conversion rises so steeply with relatively low field strengths that even the magnetic earth field should enhance the catalytic activity of nickel in compact form; a few hundred oersted may suffice for doubling the conversion and at some 1000 or 10.000 oersted a saturation value of the conversion is reached. The connection between catalytic activity and magnetism finds further support by a corresponding catalytic retentivity.From the theory of ferromagnetism, especially the studies of Néel, it is known that extremely small ferromagnetic particles of the order of magnitude of Blochs walls, i. e. some 10—4 mm, posses high permanent magnetism. This fact appears significant in this connection for the high catalytic activity of finely divided powder catalysts such as Raney catalysts. This permanent magnetism explains also the apparent lack of the external magneto-catalytic effect when using a nickel powder catalyst. The theoretical treatment of the results cannot yet give a definite explanation; before this can be given the experiments must be extended to ordinary chemical reactions. To this end the prerequisits for such experiments are being established.Independently thereof the experimental proof for the external catalytic effect serves to ascertain that the internal Hedvall effects are primarily correlated to the ferromagnetic and paramagnetic states of matter.

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Ultrafine bimetallic Pt–Ni nanoparticles immobilized on 3-dimensional N-doped graphene networks: a highly efficient catalyst for dehydrogenation of hydrous hydrazine

Journal of Materials Chemistry A ◽

10.1039/c8ta09003c ◽

2019 ◽

Vol 7 (1) ◽

pp. 112-115 ◽

Cited By ~ 28

Author(s):

Amit Kumar ◽

Xinchun Yang ◽

Qiang Xu

Keyword(s):

Catalytic Activity ◽

Reduction Method ◽

Chemical Reduction ◽

High Catalytic Activity ◽

Ni Nanoparticles ◽

Chemical Reduction Method ◽

Efficient Catalyst ◽

3 Dimensional ◽

Doped Graphene ◽

Wet Chemical

Ultrafine and uniformly dispersed bimetallic Pt–Ni nanoparticles (NPs) have been immobilized on novel 3-dimensional N-doped graphene networks (NGNs) by a facile wet chemical reduction method, which exhibit extremely high catalytic activity for the dehydrogenation of hydrazine hydrate.

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Hyperbranched Co2P nanocrystals with 3D morphology for hydrogen generation in both alkaline and acidic media

RSC Advances ◽

10.1039/c9ra02605c ◽

2019 ◽

Vol 9 (36) ◽

pp. 20612-20617

Author(s):

Xiaoyang Wang ◽

Xiaomin Tian ◽

Xiao Duan ◽

Chun Wu ◽

Wenli Pei ◽

...

Keyword(s):

Catalytic Activity ◽

Chemical Method ◽

Hydrogen Generation ◽

3D Structure ◽

Alkaline Media ◽

High Catalytic Activity ◽

Wet Chemical Method ◽

Acidic Media ◽

One Step ◽

Wet Chemical

Hyperbranched Co2P nanocrystals with 3D structure were successfully synthesized by a facile one-step wet-chemical method, which exhibit high catalytic activity and superior stability toward hydrogen evolution reaction in alkaline media.

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Enhanced catalytic activity of low-Pt content nanocatalysts supported on hollow carbon spheres for the ORR in alkaline media

MRS Advances ◽

10.1557/adv.2020.370 ◽

2020 ◽

Vol 5 (57-58) ◽

pp. 2961-2972

Author(s):

P.C. Meléndez-González ◽

E. Garza-Duran ◽

J.C. Martínez-Loyola ◽

P. Quintana-Owen ◽

I.L. Alonso-Lemus ◽

...

Keyword(s):

Catalytic Activity ◽

Anion Exchange ◽

Average Particle Size ◽

Synthesis Method ◽

Alkaline Media ◽

High Catalytic Activity ◽

Average Particle ◽

Carbon Spheres ◽

Hollow Carbon ◽

Hollow Carbon Spheres

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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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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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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CO Oxidation Efficiency and Hysteresis Behavior over Mesoporous Pd/SiO2 Catalyst

Catalysts ◽

10.3390/catal11010131 ◽

2021 ◽

Vol 11 (1) ◽

pp. 131 ◽

Cited By ~ 1

Author(s):

Rola Mohammad Al Soubaihi ◽

Khaled Mohammad Saoud ◽

Myo Tay Zar Myint ◽

Mats A. Göthelid ◽

Joydeep Dutta

Keyword(s):

Carbon Monoxide ◽

Catalytic Activity ◽

Co Oxidation ◽

Active Sites ◽

Bond Activation ◽

Dissociative Adsorption ◽

High Catalytic Activity ◽

Good Catalytic Activity ◽

Pretreatment Conditions ◽

Oxidation Efficiency

Carbon monoxide (CO) oxidation is considered an important reaction in heterogeneous industrial catalysis and has been extensively studied. Pd supported on SiO2 aerogel catalysts exhibit good catalytic activity toward this reaction owing to their CO bond activation capability and thermal stability. Pd/SiO2 catalysts were investigated using carbon monoxide (CO) oxidation as a model reaction. The catalyst becomes active, and the conversion increases after the temperature reaches the ignition temperature (Tig). A normal hysteresis in carbon monoxide (CO) oxidation has been observed, where the catalysts continue to exhibit high catalytic activity (CO conversion remains at 100%) during the extinction even at temperatures lower than Tig. The catalyst was characterized using BET, TEM, XPS, TGA-DSC, and FTIR. In this work, the influence of pretreatment conditions and stability of the active sites on the catalytic activity and hysteresis is presented. The CO oxidation on the Pd/SiO2 catalyst has been attributed to the dissociative adsorption of molecular oxygen and the activation of the C-O bond, followed by diffusion of adsorbates at Tig to form CO2. Whereas, the hysteresis has been explained by the enhanced stability of the active site caused by thermal effects, pretreatment conditions, Pd-SiO2 support interaction, and PdO formation and decomposition.

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