Abstract Single-crystalline sodium tungsten bronze (Na-WO 3 ) nanorods with typical diameters of 10–200 nm and lengths of several microns have been prepared via a simple hydrothermal method. The as-prepared Na-WO 3 nanorods crystallize in a hexagonal structure and elongate along the crystallographic direction. The as-prepared Na-WO 3 nanorods have eight diagnostic Fourier transform infrared (FTIR) absorptions at 3604, 3545, 1622, 1600, 983, 790, 480 and 430 cm −1 , which represent specific fingerprints of the vibrational features of hexagonally tunnel-structured Na-WO 3 containing tunnel water molecules. The as-prepared Na-WO 3 nanorods exhibit a typical cathodic electrochromism, which is related to a proton-electron double insertion process. X-ray diffraction results indicate a phase transformation of hexagonal Na-WO 3 nanorods during the electrochromic process, of which the involved local structural evolutions such as water decomposition and proton insertion have been discussed by using FTIR spectroscopy. The results suggest that, during the electrochromic coloration process, the inserted protons might occupy the small trigonal tunnel positions instead of the large hexagonal ones.

中文翻译：

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六方钠钨青铜纳米棒的电致变色

摘要 通过简单的水热法制备了典型直径为 10-200 nm、长度为几微米的单晶钠钨青铜 (Na-WO 3 ) 纳米棒。所制备的Na-WO 3 纳米棒以六边形结构结晶并沿结晶方向伸长。所制备的 Na-WO 3 纳米棒在 3604、3545、1622、1600、983、790、480 和 430 cm -1 处具有八个诊断傅里叶变换红外 (FTIR) 吸收，代表六边形隧道振动特征的特定指纹-结构的Na-WO 3 包含隧道水分子。所制备的Na-WO 3 纳米棒表现出典型的阴极电致变色现象，这与质子-电子双插入过程有关。X 射线衍射结果表明六方 Na-WO 3 纳米棒在电致变色过程中发生了相变，其中所涉及的局部结构演变，如水分解和质子插入，已通过使用 FTIR 光谱进行了讨论。结果表明，在电致变色过程中，插入的质子可能占据小三角隧道位置而不是大六边形隧道位置。