Journal article
Charge Dynamics in TiO2/MXene Composites
Journal of physical chemistry. C, v 125(19), pp 10473-10482
20 May 2021
Featured in Collection : UN Sustainable Development Goals @ Drexel
Abstract
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 (Ti3C2T x , 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 Ti3C2T x 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/Ti3C2T x heterostructure, hot electrons are excited only from MXene upon photon absorption at wavelengths far below the TiO2 band gap. Under these conditions, the Ti3C2T x -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 Ti3C2T x 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.
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Details
- Title
- Charge Dynamics in TiO2/MXene Composites
- Creators
- Shaun Debow - U.S. Army Combat Capabilities Development Command Chemical Biological Center, Research & Technology DirectorateTong Zhang - University of Chinese Academy of SciencesXusheng Liu - University of Electronic SciencesFuzhan Song - Department of Chemistry and BiochemistryYuqin Qian - Department of Chemistry and BiochemistryJian Han - Nanjing University of Science and TechnologyKathleen Maleski - A.J. Drexel Nanomaterials Institute and Department of Materials Science and EngineeringZachary B Zander - U.S. Army Combat Capabilities Development Command Chemical Biological Center, Research & Technology DirectorateWilliam R Creasy - Leidos Corp. Supporting U.S. Army CCDC CBCDanielle L Kuhn - U.S. Army Combat Capabilities Development Command Chemical Biological Center, Research & Technology DirectorateYury Gogotsi - A.J. Drexel Nanomaterials Institute and Department of Materials Science and EngineeringBrendan G DeLacy - U.S. Army Combat Capabilities Development Command Chemical Biological Center, Research & Technology DirectorateYi Rao - Department of Chemistry and Biochemistry
- Publication Details
- Journal of physical chemistry. C, v 125(19), pp 10473-10482
- Publisher
- American Chemical Society; Washington, DC
- Resource Type
- Journal article
- Language
- English
- Academic Unit
- Materials Science and Engineering
- Web of Science ID
- WOS:000655640900030
- Scopus ID
- 2-s2.0-85106530449
- Other Identifier
- 991015238574004721
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- Collaboration types
- Domestic collaboration
- International collaboration
- Web of Science research areas
- Chemistry, Physical
- Materials Science, Multidisciplinary
- Nanoscience & Nanotechnology