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Charge Dynamics in TiO2/MXene Composites

delete2021-04-30
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PRE
AI
S
Shaun Debow
张通 cover
张通 (Tong Zhang)
X
Xu‐Sheng Liu
F
Fuzhan Song
Y
Yuqin Qian
J
Jian Han
K
Kathleen Maleski
Z
Zachary Zander
W
William R. Creasy
D
Danielle L. Kuhn
Y
Yury Gogotsi
B
Brendan G. DeLacy
Y
Yi Rao *
DOI:10.1021/acs.jpcc.1c01543delete
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Abstract

Abstract

En 中文
Metal-semiconductor heterostructures are believed to improve hot-electron injection efficiency and influence the photocatalytic performance. Understanding the carrier dynamics at the heterostructure is essential for designing more efficient photocatalysts. Herein, we fabricated a Schottky heterostructure using two-dimensional (2D) titanium carbide MXene (Ti3C2Tx, where T-x stands for surface terminations, such as O or OH) and a TiO2 semiconductor and examined the carrier dynamics at the heterostructure using time-resolved infrared techniques. MXene exhibits robust metallic properties in terms of photoconductivity comparable to those of high-quality 2D graphene materials. The photoexcitation of MXene greatly increases the scattering rate and leads to a decreased photoconductivity. When Ti3C2Tx comes in close contact with the TiO2 semiconductor, band bending leads to the formation of a Schottky barrier at the contact junction. In this plasmonic TiO2/Ti3C2Tx heterostructure, hot electrons are excited only from MXene upon photon absorption at wavelengths far below the TiO2 band gap. Under these conditions, the Ti3C2Tx-generated plasmonic electrons are transferred into the conduction band of the TiO2 semiconductor over the Schottky barrier with a fast time constant of 180 fs. The strong electronic coupling between oxygen-terminated Ti3C2Tx and TiO2 is due to their proximity, and the resulting interactions are likely responsible for the fast electron transfer in the composites. Our results demonstrate a potential of 2D MXene materials in plasmonic applications and provide new insights into the design of MXene-based photocatalysts.
Keywords:
TITANIUM CARBIDE MXENE
HOT-ELECTRON TRANSFER
PLASMON
TI3C2
NANOFIBERS
INTERFACE
GRAPHENE
PHOTODETECTOR
GENERATION
HYBRIDS
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Journal

Journal of Physical Chemistry C cover
Journal of Physical Chemistry C
IF:
3.2
Papers:
5.6W
Citations:
15.0W

Organization

D
Drexel University
Scholars:
1.3W
Papers: 1.1W
Citations: 2.2W
U
university of chinese academy of sciences, cas
Scholars:
4.1W
Papers: 3.8W
Citations: 75
U
Utah State University
Scholars:
4.1K
Papers: 3.5K
Citations: 8.9K
U
Utah System of Higher Education
Scholars:
4.6W
Papers: 4.0W
Citations: 161
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