碳纳米管内填充生长超细一维亚化学计量比氧化钨纳米线

超细亚化学计量比过渡金属氧化物纳米材料的可控制备具有重要应用价值, 但其可控合成仍存在挑战。本研究提出了基于碳纳米管的限域空间合成法, 首先采用溶液法将四硫代钨酸铵((NH₄)₂WS₄)填充至碳管内, 然后真空热分解反应制得产物。通过表征发现: 碳管内限域生长的主要产物为一维亚氧化物W₃O₈纳米线, 其典型线宽为1.23~1.93 nm, 对应4~5列钨氧原子链, 长度可达数十微米。W₃O₈纳米线与碳管内壁之间主要为范德华力相互作用(间距约0.35 nm), 为分离及表征W₃O₈纳米线的本征特性提供了方便, 该方法也有望应用于合成其他亚化学计量比的一维过渡金属氧化物纳米线。

One-dimensional Sub-stoichiometric W3O8 Nanowires Filled Carbon Nanotubes

Nanostructured sub-stoichiometric transition metal oxides hold promising applications in many areas, while challenge still remains towards their precisely controlled synthesis, particularly for those ultrafine nanowires. In present work, a carbon nanotube (CNT) inner growth based on two-step synthetic approach was adopted to achieve one-dimensional sub-stoichiometric tungsten oxides. Ammonium tetrathiotungsten((NH₄)₂WS₄)) were encapsulated into the inner cavity of carbon nanotubes, which were thermally decomposed into tungsten oxides inside the CNTs. Characterizations confirm that the CNT-filling products are ultrafine one-dimensional W₃O₈ nanowires, that appears 1.23-1.93 nm in width (corresponding to four-five arrays of tungsten atomic column) and up tens of microns in length (close to that of CNTs). The non-noticeable size-dependent lattice parameters of the W₃O₈ nanowires and the large nanowire-CNT separation indicate a rather weak interaction between the filled W₃O₈ nanowires and host CNTs, which provides the opportunity to separate and probe the intrinsic properties of these ultrafine 1D W₃O₈ nanowires. Nevertheless, the proposed synthetic method is extendable to achieve other 1D transition metal oxides.