Park In, Han Yang-Su, Choy Jin-Ho
Green Chemistry and Manufacturing System Division, Korea Institute of Industrial Technology, Chungnam 330-825, Republic of Korea.
J Nanosci Nanotechnol. 2009 Dec;9(12):7190-4. doi: 10.1166/jnn.2009.1604.
We herein describe a soft-chemical route to exfoliation of layered semiconductive titanoniobate (KTiNbO5) into individual oxide nanosheets. The protonic layered titanoniobate (HTiNbO5), derived from KTiNbO5, is reacted with zwitterionic aminoundecanoic acid (H2N(CH2)10COOH; AUA) to replace the interlayer H+ ions with AUA molecules in an acidic aqueous solution (pH approximately 3). On intercalating amino acid molecules into titanoniobate layers, the basal spacing expands from 8.5 angstroms to 23.7 angstroms. Further expansion of the layers is achieved by a host-guest repulsive interaction via the interlayer deprotonation of the carboxylic groups of amino acid molecules in a basic aqueous solution. The exfoliated oxide nanosheets exhibit remarkable colloidal stability in aqueous solution with a significant spectral blue shift in UV optical absorption spectra. Moreover, atomic force microscopic (AFM) and scanning electron microscopic (SEM) observations directly confirm the delamination of parent microcrystals.
我们在此描述了一种将层状半导体钛铌酸钾（KTiNbO5）剥离成单个氧化物纳米片的软化学途径。由KTiNbO5衍生而来的质子化层状钛铌酸盐（HTiNbO5），在酸性水溶液（pH约为3）中与两性离子氨基十一酸（H2N(CH2)10COOH；AUA）反应，用AUA分子取代层间的H+离子。在将氨基酸分子插入钛铌酸盐层时，基面间距从8.5埃扩展到23.7埃。通过在碱性水溶液中氨基酸分子羧基的层间去质子化产生的主客体排斥相互作用，实现了层的进一步扩展。剥离的氧化物纳米片在水溶液中表现出显著的胶体稳定性，在紫外光吸收光谱中出现明显的光谱蓝移。此外，原子力显微镜（AFM）和扫描电子显微镜（SEM）观察直接证实了母体微晶的分层。
