Topic
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.
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TL;DR: In this paper, a representative selenide catalyst is entirely converted into nickel hydroxide under oxygen-evolution conditions, showing that metal selenides are unstable during oxygen evolution, and the in situ generated metal oxides are responsible for their activity.
Abstract: Efficient oxygen-evolution reaction catalysts are required for the cost-effective generation of solar fuels. Metal selenides have been reported as promising oxygen-evolution catalysts; however, their active forms are yet to be elucidated. Here we show that a representative selenide catalyst, nickel selenide, is entirely converted into nickel hydroxide under oxygen-evolution conditions. This result indicates that metal selenides are unstable during oxygen evolution, and the in situ generated metal oxides are responsible for their activity. This knowledge inspired us to synthesize nanostructured nickel iron diselenide, a hitherto unknown metal selenide, and to use it as a templating precursor to a highly active nickel iron oxide catalyst. This selenide-derived oxide catalyses oxygen evolution with an overpotential of only 195 mV for 10 mA cm(-2). Our work underscores the importance of identifying the active species of oxygen-evolution catalysts, and demonstrates how such knowledge can be applied to develop better catalysts.
779 citations
TL;DR: In this article, a general reaction on model has been established with a reaction via the solution: dissolution of the solid precursor; reduction in solution; homogeneous nucleation and growth of the metallic phase from the solution.
731 citations
TL;DR: In this paper, the effects of iron coprecipitated into thin film nickel oxide electrodes or introduced in the 25 weight percent electrolyte were studied by a combination of galvanostatic and open circuit decay methods.
Abstract: The effects of iron coprecipitated into thin film nickel oxide electrodes or introduced in the 25 weight percent electrolyte were studied by a combination of galvanostatic and open‐circuit decay methods. Effects on voltammetric behavior and on the oxygen overpotential were observed in thin film electrodes with as little as 0.01% iron present. The over‐potential was further lowered by 1% iron to the extent that the nickel oxide charge storage reaction was adversely affected. Higher concentrations of iron coprecipitated into a composite iron/nickel hydrous oxide dramatically catalyzed the oxygen evolution reaction by lowering the Tafel slope from about 70 mV/decade with no iron present to about 25 mV/decade with 10–50% iron. This composite oxide shows promise as an anodic electrocatalyst for alkaline electrolysis to produce hydrogen; the oxygen overpotential on thin film electrodes was over 200 mV lower than the overpotential with nickel oxide, itself, when polarized at 80 mA/cm2.
714 citations
TL;DR: In this paper, the authors studied the anodic oxidations of a range of organic compounds at a nickel anode in aqueous alkaline solution and proposed a mechanism to explain the behavior observed.
713 citations
TL;DR: In this paper, the removal of heavy metals such as Mn, Co, Ni, and Cu from aqueous solution is studied using a raw kaolinite. And the results show that heavy metal removal is an endothermic process and the process of adsorption is favored at high temperatures.
707 citations