27016-73-5Relevant articles and documents
Angular dependence of pinning potential, upper critical field, and irreversibility field in underdoped BaFe1.9Co0.1As 2 single crystal
Shahbazi,Wang,Ghorbani,Dou,Choi
, (2012)
Underdoped BaFe1.9Co0.1As2 single crystal was studied by angular dependence of magneto-transport at fields up to 13 T over a wide range of temperature. Our results show that pinning potential, U o, decreases slightly for 45 and remains constant for 45, while the upper critical field, Hc2, and the irreversibility field, H irr, increase with . According to anisotropic Ginzburg-Landau theory, the anisotropy was determined by scaling the resistivity under different magnetic fields below the superconducting critical temperature, Tc. Anisotropy, , in the underdoped crystal is found to be temperature dependent and decreases from 2.1 to 1.8 for as T is reduced from 17 to 12.5 K.
A new chemical route to prepare nanocrystalline cobalt monoarsenide
Wang,Qian,Zhang,Li,Xie,Qian
, p. 1129 - 1133 (1999)
A low-temperature solvothermal reduction process to nanocrystalline CoAs is reported here. All the precursors are easily accessible. The formation and crystalline temperature of CoAs could be as low as 140°C. Powder X-ray diffraction (XRD) shows a single phase of CoAs. The average particle size observed from transmission electron micrography (TEM) is about 18 nm. Elemental analysis and X-ray photoelectron spectroscopy (XPS) were utilized to determine the chemical composition of the product.
Cobalt-metalloid alloys for electrochemical oxidation of 5-hydroxymethylfurfural as an alternative anode reaction in lieu of oxygen evolution during water splitting
Weidner, Jonas,Barwe, Stefan,Sliozberg, Kirill,Piontek, Stefan,Masa, Justus,Apfel, Ulf-Peter,Schuhmann, Wolfgang
, p. 1436 - 1445 (2018/07/05)
The electrochemical water splitting commonly involves the cathodic hydrogen and anodic oxygen evolution reactions (OER). The oxygen evolution reaction is more energetically demanding and kinetically sluggish and represents the bottleneck for a commercial competitiveness of electrochemical hydrogen production from water. Moreover, oxygen is essentially a waste product of low commercial value since the primary interest is to convert electrical energy into hydrogen as a storable energy carrier. We report on the anodic oxidation of 5-hydroxymethylfurfural (HMF) to afford the more valuable product 2,5-furandicarboxylic acid (FDCA) as a suitable alternative to the oxygen evolution reaction. Notably, HMF oxidation is thermodynamically more favorable than water oxidation and hence leads to an overall improved energy efficiency for H2 production. In addition, contrary to the “waste product O2”, FDCA can be further utilized, e.g., for production of polyethylene 2,5-furandicarboxylate (PEF), a sustainable polymer analog to polyethylene terephthalate (PET) and thus represents a valuable product for the chemical industry with potential large scale use. Various cobalt-metalloid alloys (CoX; X = B, Si, P, Te, As) were investigated as potential catalysts for HMF oxidation. In this series, CoB required 180 mV less overpotential to reach a current density of 55 mA cm?2 relative to OER with the same electrode. Electrolysis of HMF using a CoB modified nickel foam electrode at 1.45 V vs RHE achieved close to 100% selective conversion of HMF to FDCA at 100% faradaic efficiency.
