Faculty of Natural Sciences

TY - JOUR

T1 - Scrutinizing particle size related bond strengthening in anatase TiO2

AU - Yu, Jinlong

AU - Mamakhel, Aref

AU - Sondergaard-Pedersen, Frederik

AU - Ceccato, Marcel

AU - Iversen, Bo Brummerstedt

PY - 2022/9

Y1 - 2022/9

N2 - A series of small, middle, and large anatase TiO2 particles were synthesized through the hydrolysis of titanium tetraisopropoxide (TTIP) to investigate the size-related chemical bond length and strength variation. Unit cell volume contraction with decreasing particle size is identified from Rietveld refinement of high-resolution synchrotron powder X-ray diffraction (PXRD) patterns. More titanium vacancies are also found for smaller anatase particles. Contrary to the variation in unit cell volume, a larger Debye temperature Theta(D)(TiO2) derived from the linear and nonlinear fitting of atomic displacement parameters (U-iso(TiO2)) as a function of temperature is revealed for smaller anatase particles. The length of the Ti-O bond is also shorter for smaller anatase particles. Furthermore, optical phonon frequencies blue-shifting with the decrease in anatase particle size are determined by Raman spectroscopy. X-ray photoelectron spectroscopy (XPS) analysis rules out the presence of a large amount of Ti3+, while optical diffuse reflectance measurement eliminates the existence of a large number of oxygen vacancies in all particles. Combining the analysis results of PXRD, thermogravimetric analysis (TGA), and Fourier-transform infrared spectroscopy (FTIR), more structural and surface hydroxyls (-OH) appear to exist in smaller anatase particles. It is the structural and surface -OH that are responsible for the size-related chemical bond length and strength variation in the as-synthesized anatase particles.

AB - A series of small, middle, and large anatase TiO2 particles were synthesized through the hydrolysis of titanium tetraisopropoxide (TTIP) to investigate the size-related chemical bond length and strength variation. Unit cell volume contraction with decreasing particle size is identified from Rietveld refinement of high-resolution synchrotron powder X-ray diffraction (PXRD) patterns. More titanium vacancies are also found for smaller anatase particles. Contrary to the variation in unit cell volume, a larger Debye temperature Theta(D)(TiO2) derived from the linear and nonlinear fitting of atomic displacement parameters (U-iso(TiO2)) as a function of temperature is revealed for smaller anatase particles. The length of the Ti-O bond is also shorter for smaller anatase particles. Furthermore, optical phonon frequencies blue-shifting with the decrease in anatase particle size are determined by Raman spectroscopy. X-ray photoelectron spectroscopy (XPS) analysis rules out the presence of a large amount of Ti3+, while optical diffuse reflectance measurement eliminates the existence of a large number of oxygen vacancies in all particles. Combining the analysis results of PXRD, thermogravimetric analysis (TGA), and Fourier-transform infrared spectroscopy (FTIR), more structural and surface hydroxyls (-OH) appear to exist in smaller anatase particles. It is the structural and surface -OH that are responsible for the size-related chemical bond length and strength variation in the as-synthesized anatase particles.

KW - ROOM-TEMPERATURE SYNTHESIS

KW - RAMAN-SCATTERING

KW - GROWTH KINETICS

KW - ZINC PHOSPHATE

KW - SURFACE

KW - NANOPARTICLES

KW - INHIBITION

KW - DEPENDENCE

KW - WATER

KW - HEAT

UR - https://pubs.rsc.org/en/content/articlepdf/2022/dt/d2dt02128e

U2 - 10.1039/d2dt02128e

DO - 10.1039/d2dt02128e

M3 - Journal article

VL - 51

SP - 13515

EP - 13526

JO - Dalton Transactions (Print Edition)

JF - Dalton Transactions (Print Edition)

SN - 1477-9226

IS - 35

ER -