scholarly journals Pd-Au Electrocatalysts for Hydrogen Evolution Reaction at Neutral pH

2014 ◽  
Vol 2014 ◽  
pp. 1-6 ◽  
Author(s):  
Elitsa Chorbadzhiyska ◽  
Mario Mitov ◽  
Georgi Hristov ◽  
Nina Dimcheva ◽  
Lori Nalbandian ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Hydrogen Evolution ◽  
Hydrogen Evolution Reaction ◽  
Phosphate Buffer Solution ◽  
Hydrogen Gas ◽  
Mass Spectrometry Analysis ◽  
Carbon Felt ◽  
Buffer Solution ◽  
Spectrometry Analysis ◽  
Scanning Electron

Pd-Au codeposits with different ratio of both metals were electrodeposited on carbon felt, characterized by scanning electron microscopy, and investigated as electrocatalysts towards hydrogen evolution reaction in neutral phosphate buffer solution. The quantities of the produced hydrogen gas with different electrocatalysts, estimated from data obtained by chronoamperometry, were confirmed by mass spectrometry analysis. The highest hydrogen evolution rate was achieved with the electrocatalysts, produced from electrolyte with equal Pd and Au content.

Field Emission Scanning Electron Microscopy Of Mouse Cerebellar Synaptic Contacts

2000 ◽  
Vol 6 (S2) ◽  
pp. 844-845
Author(s):  
O.J. Castejón ◽  
R. P. Apkarian ◽  
H. V. Castejón
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Field Emission ◽  
Cerebellar Cortex ◽  
Osmium Tetroxide ◽  
Phosphate Buffer Solution ◽  
Buffer Solution ◽  
Solution Ph ◽  
Osmium Tetroxide Solution ◽  
Scanning Electron

Samples of albino mice cerebellar cortex were processed by the cryofracture method for scanning electron microscopy and examined with the field emission scanning electron microscope (FESEM). Albino mouse cerebellar cortex was excised, cut into 1-2 mm slices and inmersed in 4% glutaraldehyde in O. l M phosphate buffer solution, pH 7.4, for 24h at 4°C; and postfixed for 1 h in a similarly buffered 1% osmium tetroxide solution. Specimens were dehydrated in a graded serie of ethanol (30, 50, 70, 80, 90 2x100%) prior to wrapping individual tissue pieces in preformed absolute ethanol filled parafilm cryofracture packets. Rapid freezing of packets was performed by plunging into LN2. First, the packet was transferred from the LN2 storage vessel with LNT chilled forceps in order to avoid themial damage. Secondly, the cooled fracture blade was removed from the LN2, the packet was orientated under the blade, and immediately struck with a heavy tool.

A rapid fixation method for transmission and Scanning Electron Microscopy using microwave irradiation

1990 ◽  
Vol 48 (3) ◽  
pp. 760-761
Author(s):  
Yasuaki Hotta ◽  
Masumi Nozaki ◽  
Nobuhiko Honda ◽  
Hiroyuki Kato ◽  
Ying Wei Wang ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Microwave Irradiation ◽  
Phosphate Buffer Solution ◽  
Male Rats ◽  
Fixation Method ◽  
Buffer Solution ◽  
Wistar Strain ◽  
Microwave Fixation ◽  
Scanning Electron

Recently, the validity of microwave irradiation (MWI) for electron microscopy has attracted special interest especially in Japan. Recently, we developed a new maceration method for scanning electron microscopy (microwave maceration) and a rapid polymerization method for tissue embedding using epoxy resin (microwave polymerization). Concerning the tissue fixations using MWI (microwave fixation), there are many problems which are not yet clear. In this study, we intend to reveal the effectiveness and mechanism of microwave fixation for scanning and transmission electron mi c roscopy.Liver and trachea taken from Wistar strain male rats were used in this experiment. The fresh livers and tracheae were cut into small pieces and microwave irradiated using a microwave processor (H2500, Bio-Rad) for 1 or 3 min in 2.5% g1utara 1dehyde (GL) bufferized fixatives regulated at pH 7.3 with 0.1M phosphate buffer solution. To prevent the rising of temperature during MWI, specially designed metal case containing water and ice was used (Fig.1).

Preparation of Ni-Doped MoS2 Microsphere and its Superior Electrocatalytic Hydrogen Evolution Ability

2013 ◽  
Vol 871 ◽  
pp. 206-210 ◽  
Author(s):  
Yue Chan Xie ◽  
Yue Ming Li
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Hydrogen Evolution ◽  
Hydrogen Evolution Reaction ◽  
Undoped Sample ◽  
Cathodic Current ◽  
X Ray ◽  
Effective Hydrogen ◽  
Scanning Electron ◽  
Mos2 Catalyst

To find a cheap and effective hydrogen evolution reaction catalyst, a series of Ni-doped MoS2 microspheres consisting of MoS2 nanosheets have been prepared via hydrothermal synthesis and characterized by scanning electron microscopy (SEM), and X-ray powder diffraction (XRD). Their performance as electrochemical hydrogen evolution reaction (HER) catalyst was studied. It is found that the Ni-doped MoS2 exhibited superior electrocatalytic activity in the HER to undoped MoS2 catalysts. The overpotential of Ni-doped MoS2 has decreased compared with that of undoped sample, indicating an improved activity in HER. Furthermore, the cathodic current for the Ni-doped MoS2 catalyst is about 9 times as much as that for undoped MoS2. Based on our findings, the resulting Ni-doped MoS2 might be promising inexpensive alternative to platinum catalysts in hydrogen production.

scholarly journals Amorphous Ni x Co y P-supported TiO2 nanotube arrays as an efficient hydrogen evolution reaction electrocatalyst in acidic solution

2019 ◽  
Vol 10 ◽  
pp. 62-70 ◽  
Author(s):  
Yong Li ◽  
Peng Yang ◽  
Bin Wang ◽  
Zhongqing Liu
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Hydrogen Evolution ◽  
Hydrogen Evolution Reaction ◽  
Photoelectron Spectroscopy ◽  
Electrochemical Impedance ◽  
Nanotube Arrays ◽  
Active Surface Area ◽  
X Ray ◽  
Transmission Electron

Bimetallic phosphides have been attracting increasing attention due to their synergistic effect for improving the hydrogen evolution reaction as compared to monometallic phosphides. In this work, NiCoP modified hybrid electrodes were fabricated by a one-step electrodeposition process with TiO2 nanotube arrays (TNAs) as a carrier. X-ray diffraction, transmission electron microscopy, UV–vis diffuse reflection spectroscopy, X-ray photoelectron spectroscopy and scanning transmission electron microscopy/energy-dispersive X-ray spectroscopy were used to characterize the physiochemical properties of the samples. The electrochemical performance was investigated by cyclic voltammetry, linear sweep voltammetry, and electrochemical impedance spectroscopy. We show that after incorporating Co into Ni–P, the resulting Ni x Co y P/TNAs present enhanced electrocatalytic activity due to the improved electron transfer and increased electrochemically active surface area (ECSA). In 0.5 mol L−1 H2SO4 electrolyte, the Ni x Co y P/TNAs (x = 3.84, y = 0.78) demonstrated an ECSA value of 52.1 mF cm−2, which is 3.8 times that of Ni–P/TNAs (13.7 mF cm−2). In a two-electrode system with a Pt sheet as the anode, the Ni x Co y P/TNAs presented a bath voltage of 1.92 V at 100 mA cm−2, which is an improvment of 79% over that of 1.07 V at 10 mA cm−2.

Hydrothermal Synthesis of Few-Layer and Edge-Rich Cobalt-Doped Molybdenum Selenide/Nitrogenated Graphene Composite and Investigation of Its Electrocatalytic Activity for Hydrogen Evolution Reaction

NANO ◽  
2016 ◽  
Vol 11 (10) ◽  
pp. 1650107 ◽  
Author(s):  
Ming Ou ◽  
Lin Ma ◽  
Limei Xu ◽  
Zhuomei Yang ◽  
Haizhen Li
Keyword(s):  
Electron Microscopy ◽  
Hydrogen Evolution ◽  
Hydrogen Evolution Reaction ◽  
Photoelectron Spectroscopy ◽  
Hydrothermal Route ◽  
X Ray ◽  
Graphene Composite ◽  
Molybdenum Selenide ◽  
Nitrogen Doped Graphene ◽  
Doped Graphene

Cobalt-doped MoSe2/nitrogenated graphene composite has been successfully synthesized via a facile hydrothermal route and is investigated as an electrocatalyst for hydrogen evolution reaction (HER). The as-prepared samples are well characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HRTEM), X-ray photoelectron spectroscopy (XPS) and Raman spectrum. The results reveal that Co-doped MoSe2 nanosheets which are characteristic of few layers (2–4 layers) and abundant exposed active edge sites are well anchored on the nitrogen-doped graphene sheets to constitute robust composites. When evaluated as catalysts for HER, the obtained composites demonstrate superior electrocatalytic activities toward HER.

Efficient electrocatalytic hydrogen gas evolution by a cobalt–porphyrin-based crystalline polymer

2018 ◽  
Vol 47 (26) ◽  
pp. 8801-8806 ◽  
Author(s):  
Yanyu Wu ◽  
José M. Veleta ◽  
Diya Tang ◽  
Alex D. Price ◽  
Cristian E. Botez ◽  
...  
Keyword(s):  
Hydrogen Evolution ◽  
Hydrogen Evolution Reaction ◽  
Aqueous Media ◽  
Crystalline Polymer ◽  
Hydrogen Gas ◽  
Gas Evolution ◽  
Polymeric System ◽  
Cobalt Porphyrin

Herein, we report a crystalline CoTcPP-based [TcPP = the anion of meso-tetra(4-carboxyphenyl)porphyrin] polymeric system, 1, as a hydrogen evolution reaction (HER) electrocatalyst in acidic aqueous media.

scholarly journals MoSe2-GO/rGO Composite Catalyst for Hydrogen Evolution Reaction

Polymers ◽  
2018 ◽  
Vol 10 (12) ◽  
pp. 1309 ◽  
Author(s):  
Wenwu Guo ◽  
Quyet Le ◽  
Amirhossein Hasani ◽  
Tae Lee ◽  
Ho Jang ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Graphene Oxide ◽  
Hydrogen Evolution ◽  
Hydrogen Evolution Reaction ◽  
Photoelectron Spectroscopy ◽  
Transition Metal Dichalcogenides ◽  
Catalytic Performance ◽  
Composite Catalyst ◽  
X Ray ◽  
Molybdenum Selenide

There has been considerable research to engineer composites of transition metal dichalcogenides with other materials to improve their catalytic performance. In this work, we present a modified solution-processed method for the formation of molybdenum selenide (MoSe2) nanosheets and a facile method of structuring composites with graphene oxide (GO) or reduced graphene oxide (rGO) at different ratios to prevent aggregation of the MoSe2 nanosheets and hence improve their electrocatalytic hydrogen evolution reaction performance. The prepared GO, rGO, and MoSe2 nanosheets were characterized by X-ray powder diffraction, Raman spectroscopy, X-ray photoelectron spectroscopy, transmission electron microscopy, energy-dispersive X-ray spectroscopy, and scanning electron microscopy. The electrocatalytic performance results showed that the pure MoSe2 nanosheets exhibited a somewhat high Tafel slope of 80 mV/dec, whereas the MoSe2-GO and MoSe2-rGO composites showed lower Tafel slopes of 57 and 67 mV/dec at ratios of 6:4 and 4:6, respectively. We attribute the improved catalytic effects to the better contact and faster carrier transfer between the edge of MoSe2 and the electrode due to the addition of GO or rGO.

Fabrication and Characterization of Amorphous Cobalt-Doped Molybdenum Sulfide for Hydrogen Evolution Reaction

2015 ◽  
Vol 15 (10) ◽  
pp. 8257-8262 ◽  
Author(s):  
Dongwook Lim ◽  
Hyein Hwang ◽  
Taewoo Kim ◽  
Sang Eun Shim ◽  
Sung-Hyeon Baeck
Keyword(s):  
Electron Microscopy ◽  
Hydrogen Evolution ◽  
Hydrogen Evolution Reaction ◽  
Photoelectron Spectroscopy ◽  
Water Electrolysis ◽  
Molybdenum Sulfide ◽  
Intrinsic Activity ◽  
Metal Catalyst ◽  
Alkaline Water Electrolysis ◽  
Catalytic Hydrogen Evolution

In the present study, hydrogen evolution reaction (HER) by alkaline water electrolysis was conducted without using a precious metal catalyst. We synthesized an amorphous cobalt-doped molybdenum sulfide by electrodeposition using different cobalt loadings. The amorphous Co-MoSx produced was characterized by scanning electron microscopy, transmission electron microscopy, and X-ray photoelectron spectroscopy. The cobalt doping and sulfidation procedure resulted in the successful fabrication of a candidate catalyst for the catalytic hydrogen evolution in alkaline solution with high intrinsic activity. Cobalt incorporated amorphous MoSx exhibited 3 times higher HER activity than non-promoted MoSx.

Synthesis, Characterization and In Vitro Drug Release of Melphalan Magnetic Microspheres

2013 ◽  
Vol 22 ◽  
pp. 31-40
Author(s):  
Jin Qiao Xu ◽  
Hai Xing Xu ◽  
Zubad Newaz ◽  
Ran Li ◽  
Yu Zhang ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Drug Release ◽  
Drug Loading ◽  
Phosphate Buffer Solution ◽  
Magnetic Microspheres ◽  
Targeted Chemotherapy ◽  
Buffer Solution ◽  
Magnetization Measurements ◽  
Co Precipitation

A new method of reversible association of melphalan (MEL) to magnetic Fe3O4 nanoparticles preparing MEL magnetic microspheres was developed for magnetically targeted chemotherapy. The efficacy of this approach was evaluated in terms of encapsulation efficiency (EE), drug loading content (DLC), delivery properties and cytotoxicity in vitro. Magnetic Fe3O4 nanoparticles were synthesized by co-precipitation methods and characterized by X-ray diffraction (XRD), fourier transform infrared spectroscopy (FTIR), transmission electron microscopy (TEM) and magnetization measurements. The MEL magnetic microspheres were obtained through emulsion cross-linking method and characterized by FTIR, magnetization measurements and scan electron microscopy (SEM). The EE and DLC were determined using a Spectro Vision DB-18805 spectrophotometer. The MEL magnetic microspheres showed good EE values, between 60.6% and 75.6%, as well as good DLC values, between 16.7% and 32.2%, and the magnetic properties were not significantly affected by incorporation of the drug. The in vitro drug release study was carried out in phosphate buffer solution (PBS), simulating physiologic body fluid conditions at 37o C with pH = 7.4. The release profiles showed an initial fast release rate, which decreased as time progressed; about 60% of the drug was released in the first 4 h, and about 78.23 % had been released after 24 h. The results indicated that the prepared magnetic microspheres may be useful for potential applications of MEL for magnetically targeted chemotherapy.

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