Probing titanate nanowire surface acidity through methylene blue adsorption in colloidal suspension and on thin films

详细信息    查看全文

• 作者：Endre Horv谩th ; Istv谩n Szil谩gyi ; L谩szl贸 Forr贸 ; Arnaud Magrez
• 关键词：Dye-sensitized solar cells ; Titanate nanowire ; Surface charge ; Adsorption ; Photocatalysis
• 刊名：Journal of Colloid and Interface Science
• 出版年：15 February, 2014
• 年：2014
• 卷：416
• 期：Complete
• 页码：190-197
• 全文大小：1660 K

文摘

The interaction of the cationic dye methylene blue (MB) with titanate nanowires (TiONWs) was investigated in different pH environments using visible spectroscopy and electrophoresis on thin films as well as in aqueous suspension. The surface charge of the TiONWs depends on the pH and ionic strength leading to positive charge under acidic and negative under alkaline conditions. The TiONWs have the same adsorption capacity on films and in suspensions at neutral pH while under alkaline conditions they are able to adsorb significantly more MB in suspension due to their higher surface area. Detailed adsorption studies in water revealed that dye cations form monomers, dimers and larger aggregates of H-type (face-to-face) on the TiONW films. The results indicate that below pH = 4.0 the TiONWs鈥?external surface consists of Br酶ntsted acid sites capable of protonating MB. It was suggested that reversible indicator role of MB molecule dimers probes the TiONW surface acidity (Br酶ntsted sites).