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. 2023 Jul 21;13(14):2125.
doi: 10.3390/nano13142125.

Construction of Built-In Electric Field in TiO2@Ti2O3 Core-Shell Heterojunctions toward Optimized Photocatalytic Performance

Tingting Hu  1   2 , Panpan Feng  3 , Liping Guo  2 , Hongqi Chu  2 , Fusheng Liu  1
Affiliations

Construction of Built-In Electric Field in TiO2@Ti2O3 Core-Shell Heterojunctions toward Optimized Photocatalytic Performance

Tingting Hu et al. Nanomaterials (Basel). .

Abstract

A series of Ti2O3@TiO2 core-shell heterojunction composite photocatalysts with different internal electric fields were synthesized using simple heat treatment methods. The synthesized Ti2O3@TiO2 core-shell heterojunction composites were characterized by means of SEM, XRD, PL, UV-Vis, BET, SPV, TEM and other related analytical techniques. Tetracycline (TC) was used as the degradation target to evaluate the photocatalytic performance of the synthesized Ti2O3@TiO2 core-shell heterojunction composites. The relevant test results show that the photocatalytic performance of the optimized materials has been significantly enhanced compared to Ti2O3, while the photocatalytic degradation rate has increased from 28% to 70.1%. After verification via several different testing and characterization techniques, the excellent catalytic performance is attributed to the efficient separation efficiency of the photogenerated charge carriers derived from the built-in electric field formed between Ti2O3 and TiO2. When the recombination of electrons and holes is occupied, more charges are generated to reach the surface of the photocatalyst, thereby improving the photocatalytic degradation efficiency. Thus, this work provides a universal strategy to enhance the photocatalytic performance of Ti2O3 by coupling it with TiO2 to build an internal electric field.

Keywords: Ti2O3@TiO2 core-shell heterojunction; built-in electric field; photocatalysis.

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Conflict of interest statement

The authors declare no conflict of interest.

Figures

Figure 1
Figure 1
Optical photos of the Ti2O3@TiO2 heterojunction at different heat treatment temperatures.
Figure 2
Figure 2
Optical photos of Ti2O3 at different heat treatment temperatures.
Figure 3
Figure 3
SEM images of Ti2O3 under different heat treatment temperatures: (a) Ti2O3; (b) Ti2O3-400; (c) Ti2O3-500; (d) Ti2O3-550; (e) Ti2O3-600; and (f) Ti2O3-700.
Figure 4
Figure 4
XRD spectra of Ti2O3, Ti2O3-100, Ti2O3-200, Ti2O3-300, Ti2O3-400, Ti2O3-450, Ti2O3-500, Ti2O3-550, Ti2O3-600, and Ti2O3-700.
Figure 5
Figure 5
(a,b) High-resolution TEM image of the Ti2O3-550 after high-temperature heat treatment.
Figure 6
Figure 6
(a) N2 adsorption–desorption isotherms of Ti2O3 at different heat treatment temperatures. (b) Pore size distribution curve of Ti2O3 at different heat treatment temperatures.
Figure 7
Figure 7
(a) Ultraviolet visible absorption spectra of the Ti2O3 and Ti2O3/TiO2 heterojunctions (Ti2O3-550, Ti2O3-600, and Ti2O3-700) and (b) the corresponding Kubelka–Munk conversion reflection spectra.
Figure 8
Figure 8
(a) Photogenerated current of the pure Ti2O3 and Ti2O3-400, Ti2O3-500, Ti2O3-550, and Ti2O3-600, and (b) the photocatalytic degradation performance of tetracycline.
Figure 9
Figure 9
Surface photovoltage (SPV) diagrams of the Ti2O3 and Ti2O3/TiO2 heterojunctions: (a) Ti2O3, (b) Ti2O3-400, (c) Ti2O3-500, (d) Ti2O3-550, and (e) Ti2O3-600.
Figure 10
Figure 10
Mott–Schottky diagrams of the Ti2O3 and Ti2O3/TiO2 heterojunctions: (a) Ti2O3, (b) Ti2O3-500, (c) Ti2O3-550, and (d) Ti2O3-600.
Figure 11
Figure 11
Schematic diagram of photocatalytic TC degradation over the Ti2O3@TiO2 heterojunctions.
See this image and copyright information in PMC

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