TY - JOUR
T1 - An Experimental and Theoretical Approach to Understanding the Surface Properties of One-Dimensional TiO2 Nanomaterials
AU - Selmani, Atida
AU - Špadina, Mario
AU - Plodinec, Milivoj
AU - Delač Marion, Ida
AU - Willinger, Marc Georg
AU - Lützenkirchen, Johannes
AU - Gafney, Harry D.
AU - Redel, Engelbert
N1 - Publisher Copyright:
© 2015 American Chemical Society.
PY - 2015/8/27
Y1 - 2015/8/27
N2 - The present research focuses on the comparative investigation of the acid-base surface properties (the isoelectric point, pHiep and point of zero charge, pHpzc) of one-dimensional TiO2 nanomaterials. Different one-dimensional TiO2 nanomaterials, nanotubes (NTs) and nanowires (NWs) were prepared by an alkaline hydrothermal synthesis procedure. The structural properties of the synthesized TiO2 nanomaterials were investigated with high-resolution scanning electron microscopy (HR-SEM), transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HR-TEM), atomic force microscopy (AFM), powder X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). The NWs and NTs were characterized using Raman and Fourier transform infrared (FT-IR) spectroscopy as well as Brunauer-Emmett-Teller (BET) measurements. Surface properties, i.e. pHiep and pHpzc of NWs and NTs were determined from electrokinetic measurements, potentiometric mass and electrolyte titrations. The relative acidity for the NWs is found to be in the interval 3 < pHiep < 4 in comparison with the NTs, with 4 < pHiep < 6. The observed differences in the relative acidity are correlated with differences in crystal structure of the studied nanomaterials and their resulting morphology. In addition, our results reveal a strong electrolyte effect on the characteristic points, pHiep and pHpzc, especially the higher cation affinity for both TiO2 nanomaterials surfaces that has a significant effect on the pH of the system. Application of the multisite complexation (MUSIC) model yields a satisfactory description of the electrokinetic data and can explain observed salt effect. (Graph Presented).
AB - The present research focuses on the comparative investigation of the acid-base surface properties (the isoelectric point, pHiep and point of zero charge, pHpzc) of one-dimensional TiO2 nanomaterials. Different one-dimensional TiO2 nanomaterials, nanotubes (NTs) and nanowires (NWs) were prepared by an alkaline hydrothermal synthesis procedure. The structural properties of the synthesized TiO2 nanomaterials were investigated with high-resolution scanning electron microscopy (HR-SEM), transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HR-TEM), atomic force microscopy (AFM), powder X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). The NWs and NTs were characterized using Raman and Fourier transform infrared (FT-IR) spectroscopy as well as Brunauer-Emmett-Teller (BET) measurements. Surface properties, i.e. pHiep and pHpzc of NWs and NTs were determined from electrokinetic measurements, potentiometric mass and electrolyte titrations. The relative acidity for the NWs is found to be in the interval 3 < pHiep < 4 in comparison with the NTs, with 4 < pHiep < 6. The observed differences in the relative acidity are correlated with differences in crystal structure of the studied nanomaterials and their resulting morphology. In addition, our results reveal a strong electrolyte effect on the characteristic points, pHiep and pHpzc, especially the higher cation affinity for both TiO2 nanomaterials surfaces that has a significant effect on the pH of the system. Application of the multisite complexation (MUSIC) model yields a satisfactory description of the electrokinetic data and can explain observed salt effect. (Graph Presented).
UR - http://www.scopus.com/inward/record.url?scp=84940472010&partnerID=8YFLogxK
U2 - 10.1021/acs.jpcc.5b02027
DO - 10.1021/acs.jpcc.5b02027
M3 - Article
AN - SCOPUS:84940472010
SN - 1932-7447
VL - 119
SP - 19729
EP - 19742
JO - Journal of Physical Chemistry C
JF - Journal of Physical Chemistry C
IS - 34
ER -