Paraotwayite-type α-Ni(OH)2 Nanowires: Structural, Optical, and Electrochemical Properties
Paraotwayite-type α-Ni(OH)2 Nanowires: Structural, Optical, and Electrochemical Properties
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DOI：
10.1021/jp405149d
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发表时间：
2013-08-22
影响因子：
3.7
通讯作者：
Jelle, Bjorn Petter
中科院分区：
文献类型：
--
作者：
Gao, Tao;Jelle, Bjorn Petter
通过简单的水热合成法制备了典型直径为2030 nm、长度可达数微米的副水滑石型氢氧化镍[Ni（OH）（2）]纳米线。纳米线的平均组成为Ni（OH）1.64（SO 4）0.18中心点0.3H（2）O，呈层状单斜结构（晶胞参数：a = 0.78867（1）nm，B = 0.29661（3）nm，c = 1.35164（2）nm，β = 91.1度），其与α-Ni（OH）（2）同构并且具有夹在二维Ni（OH）（2）主层中的硫酸根阴离子和水分子。所制备的Paraotwayite型α-Ni（OH）（2）纳米线显示出间接允许电子跃迁，带隙能量Eg约为3.8 eV，而由Paraotwayite型α-Ni（OH）（2）纳米线前体的拓扑转变获得的相应NiO纳米线显示出直接允许电子跃迁，带隙能量Eg约为3.8 eV。在碱性水溶液中，α-Ni（OH）（2）纳米线和NiO纳米线的电化学氧化还原反应相似，而α-Ni（OH）（2）纳米线由于其固有的层状结构，OH离子的插入/拔出反应大大增强.结果表明，所制备的α-Ni（OH）（2）纳米线呈现出与Ni 2+中心点Ni 3+的氧化还原电对相关的阳极电致变色，对应于从浅绿色到深棕色的颜色。副水钒石型α-Ni（OH）（2）纳米线是一种新型的光电化学器件和储能材料。
Paraotwayite-type nickel hydroxide [Ni(OH)(2)] nanowires with typical diameters of 2030 nm and lengths up to several micrometers were prepared via a simple hydrothermal synthesis. The as-prepared nanowires had a mean composition of Ni(OH)1.64(SO4)0.18 center dot 0.3H(2)O and crystallized in a layered monoclinic structure (unit cell parameters: a = 0.78867(1) nm, b = 0.29661(3) nm, c = 1.35164(2) nm, and beta = 91.1 degrees), which is isostructural to alpha-Ni(OH)(2) and has sulfate anions and water molecules sandwiched in the two-dimensional Ni(OH)(2) principle layers. The as-prepared Paraotwayite-type alpha-Ni(OH)(2) nanowires showed an indirect-allowed electron transition with a band gap energy Eg of about 3.8 eV, whereas the corresponding NiO nanowires obtained from a topotactic transformation of Paraotwayite-type alpha-Ni(OH)(2) nanowire precursors exhibited a direct-allowed electron transition with a similar band gap energy of Eg 3.8 eV. Both Paraotwayite-type alpha-Ni(OH)(2) nanowires and NiO nanowires performed similar electrochemical redox reactions in aqueous alkaline solutions, whereas the OH ion insertion/extraction reactions were found to be greatly enhanced in Paraotwayite-type alpha-Ni(OH)(2) nanowires due to their intrinsic layered structure. The as-prepared Paraotwayite-type alpha-Ni(OH)(2) nanowires exhibited an anodic electrochromism related to the redox couple of Ni2+center dot Ni3+, which corresponds to the coloration from light green to dark brown. Paraotwayite-type alpha-Ni(OH)(2) nanowires are an interesting material system for photoelectrochemical devices and energy-storage applications.