Nickel

About: Nickel is a research topic. Over the lifetime, 79308 publications have been published within this topic receiving 1210058 citations. The topic is also known as: Ni & element 28.

The magnetic moment distribution around transition element impurities in iron and nickel

Abstract: The spatial distribution of magnetic moment disturbance around fifteen different transition metal impurities in iron (Ti, V, Cr, Mn, Co, Ni, Mo, Ru, Rh, Pd, W, Re, Os, Ir and Pt) and around four such impurities in nickel (V, Cr, Mn and Fe) has been investigated A neutron scattering technique was employed that gives information on the spherically averaged moment distribution out to large distances from the impurity atom (similar 10 A) V, Cr, Co, Ni, Mo, Ru, Rh, Pd, W, Re, Os, Ir and Pt produce a small net increase in moment on iron atoms around an impurity site Those elements that lie to the right of iron in the periodic table, Co, N1, etc, seem to produce a uniformly positive disturbance in the iron matrix while the remaining elements give a positive disturbance which is apparently confined to a region of a radial extent of approximately 5 A All the solutes produce a loss of moment relative to pure iron at the impurity atom sites The impurity atom moments are generally consistent with those measurements that are available for the more concentrated alloys Around iron impurities in nickel the moment disturbance is effectively confined to the solute atom site On the other hand vanadium or chromium impurities reduce the magnetic moment on neighbouring nickel atoms very markedly The latter system is studied over a range of solute concentrations

A structurally versatile nickel phosphite acting as a robust bifunctional electrocatalyst for overall water splitting

Abstract: The design and development of economical and highly efficient electrocatalysts for the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) under alkaline conditions are vital in lowering the overall energy losses in alkaline water electrolysis. Here we present a nickel phosphite, Ni11(HPO3)8(OH)6, belonging to the unique class of phosphorus-based inorganic materials with striking structural features that have been explored for the first time in the reaction of electrocatalytic overall water splitting with a profound understanding of the system using in situ and ex situ techniques. When electrophoretically deposited, the nickel phosphite exhibited remarkable electrocatalytic activity, yielding considerably low overpotentials for both the OER and HER with extreme structural stability and enhanced durability in alkaline media. Apart from the attractive structural merits, the higher activity of nickel phosphite is mainly attributed to the formation of oxidized nickel species in the catalytic OER process, while subtle experimental evidence of the participation of phosphite anions for the acceleration of the HER with the support of Ni2+ cations as catalytically active sites is identified, which is highly compelling and has never been previously discovered. Finally, the bifunctionality of nickel phosphite was demonstrated by constructing an alkaline water electrolyzer with a low cell voltage and over 4 days of undiminishing stability. This work offers an appealing cost-effective system based on earth-abundant metals for water electrolysis and can be extended to other transition metal based homo- or hetero-bimetallic phosphites.