[The surface states and the electron-hole pair recombination of TiO2 nanopowders].

Guang Pu Xue Yu Guang Pu Fen Xi

Key Laboratory for Silicate Materials Science and Engineering of Ministry of Education, Wuhan University of Science and Technology, Wuhan 430070, China.

Published: February 2006

The nanometer TiO2 was prepared by sol-gel method. The structure and composition of the nanometer TiO2 were analyzed in detail by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and Fourier transform infrared spectrometry (FTIR). The UV-visible spectrum and fluorescence spectrum were studied too. The results show that the nanometer TiO2 contains better anatase crystallinity, and the average size of the nanometer TiO2 is about 10 nm. The surface states, Ti-OH and Ti-H2O, are formed on the surface of nanometer TiO2 in aqueous solution because of high absorption ability, whose energy levels are about 0.6 and 0. 54 eV above the valence band, respectively. The surface state Ti-H2O is destroyed after heat treatment at 500 DC for two hours, but the Ti-OH still exists, and the crystalline lattice presents some oxygen vacancies whose energy level is about 3.13 eV above valence band. For the nanometer TiO2 aqueous solution, the surface recombination of electron-hole pairs via Ti-OH and Ti-H2O is the main recombination manner, but for the samples after heat treatment, direct recombination from conduction band to valence band is the main recombination manner, due to the destroying of surface states, with the companion of indirect recombination via oxygen vacancy and surface recombination via Ti-OH.

Download full-text PDF

Source

Publication Analysis

Top Keywords

nanometer tio2
24
surface states
12
valence band
12
ti-oh ti-h2o
8
tio2 aqueous
8
aqueous solution
8
heat treatment
8
surface recombination
8
main recombination
8
recombination manner
8

Similar Publications

The ability to characterize periodic nanostructures in the laboratory gains more attention as nanotechnology is widely utilized in a variety of application fields. Scanning-free grazing-emission X-ray fluorescence spectroscopy (GEXRF) is a promising candidate to allow non-destructive, element-sensitive characterization of sample structures down to the nanometer range for process engineering. Adopting a complementary metal-oxide semiconductor (CMOS) detector to work energy-dispersively single-photon detection, the whole range of emission angles of interest can be recorded at once.

View Article and Find Full Text PDF

Highly stable 3D cellulose micro-rolls support TiO for efficient photocatalysis degradation experiment under weak light conditions.

Int J Biol Macromol

January 2025

College of Chemistry and Materials Engineering, Zhejiang A&F University, Hangzhou, Zhejiang Province 311300, PR China. Electronic address:

Immobilization of nanometer-scale photocatalysts on a 3D polymeric substrate could play several complementary roles in photocatalysis, such as providing mechanical stability, facilitating easy recycling after usage, enhancing adsorption capability, and improving light harvesting properties through multiple reflections. To achieve stable and efficient photocatalysis under weak light conditions, 3D cellulose micro-rolls were introduced into the photocatalytic composites. Here, the formation of micro-rolls is attributed to the presence of titania nanoparticles, which generate uneven shrinkage stress in cellulose during the freeze-drying process, thereby inducing the cellulose to curl up.

View Article and Find Full Text PDF

Au@TiO Core-Shell Nanoparticles with Nanometer-Controlled Shell Thickness for Balancing Stability and Field Enhancement in Plasmon-Enhanced Photocatalysis.

ACS Nano

December 2024

Antwerp engineering, photoelectrochemistry and sensing (A-PECS), Department of Bioscience Engineering, University of Antwerp, Groenenborgerlaan 171, Antwerp 2020, Belgium.

Plasmonic core-shell nanostructures can make photocatalysis more efficient for several reasons. The shell imparts stability to the nanoparticles, light absorption is expanded, and electron-hole pairs can be separated more effectively, thus reducing recombination losses. The synthesis of metal@TiO core-shell nanoparticles with nanometer control over the shell thickness and understanding its effect on the resulting photocatalytic efficiency still remains challenging.

View Article and Find Full Text PDF

We explore the low-temperature limit of atomic layer deposition of Pt using MeCpPtMe and O. We reveal that by supplying a sufficiently high O exposure, highly dispersed and thermally stable Pt sub-nanometer clusters can be deposited onto the surface of P25 TiO nanoparticles even at room temperature by atmospheric-pressure ALD.

View Article and Find Full Text PDF

The rapid expansion of the biodiesel industry has substantially increased crude glycerol residue (CG) production, creating sustainability and economic challenges due to surplus glycerol generation. Conventional purification methods are costly and environmentally demanding, necessitating innovative strategies to utilize this residue effectively. This study innovates by exploring the microwave-assisted synthesis of carbon dots (CDs) from CG, exemplifying a shift toward sustainable biodiesel production by transforming the residue into a multifunctional material.

View Article and Find Full Text PDF

Want AI Summaries of new PubMed Abstracts delivered to your In-box?

Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!