Applications of in Situ Raman Spectroscopy for Identifying Nickel Hydroxide Materials and Surface Layers during Chemical Aging

作者：David S. Hall, D. J. Lockwood, Shawn Poirier, Christina Bock, B. MacDougall · 发表于：ACS Applied Materials & Interfaces · 年份：2014 · DOI：10.1021/am405419k · 被引用次数：133 · 研究领域：Transition Metal Oxide Nanomaterials、Copper-based nanomaterials and applications、Supercapacitor Materials and Fabrication

The applications of in situ vibrational spectroscopy for identifying bulk and surface Ni(OH)2 are discussed. Raman spectra from α- and β-Ni(OH)2 samples immersed in water are generally similar to those collected from comparable dry samples. However, the Raman scattering intensities vary, and dry β-Ni(OH)2 additionally exhibits a surface O-H stretching mode at 3690 cm(-1). Using in situ Raman spectroscopy, the spontaneous transformation of α-Ni(OH)2 to β-Ni(OH)2 in room-temperature water was monitored. Such transformations are conventionally performed in high-temperature alkaline media. An intralayer OH-diffusion model is proposed. Internal stresses at the α/β-phase boundary caused shifted peaks, higher order vibrational modes, and a new water peak at 3520 cm(-1). We conclude that Raman spectroscopy may be applied to observe Ni(OH)2 materials in situ during chemical and electrochemical treatments. Such measurements provide information on the proportions of α- and β-Ni(OH)2 and their fine structural details with high sensitivity.