Interfacial potassium induced enhanced Raman spectroscopy for single-crystal TiO2 Nanowhisker

Abstract

Structural control and element doping are two popular strategies to produce semiconductors with surface enhanced Raman spectroscopy (SERS) properties. For TiO 2 based SERS substrates, maintaining a good crystallinity is critical to achieve excellent Raman scattering. At elevated temperatures (> 600 °C), the phase transition from anatase to rutile TiO 2 could result in a poor SERS performance. In this work, we report the successful synthesis of TiO 2 nanowhiskers with excellent SERS properties. The enhancement factor, an index of SERS performance, is 4.96 × 10 6 for methylene blue molecule detecting, with a detection sensitivity around 10 −7 mol·L −1. Characterizations, such as XRD, Raman, TEM, UV–vis and Zeta potential measurement, have been performed to decrypt structural and chemical characteristics of the newly synthesized TiO 2 nanowhiskers. The photo absorption onset of MB adsorbed TiO 2 nanowhiskers was similar to that of bare TiO 2 nanowhiskers. In addition, no new band was observed from the UV–vis of MB modified TiO 2 nanowhiskers. Both results suggest that the high enhancement factor cannot be explained by the charge-transfer mechanism. With the support of ab initio density functional theory calculations, we reveal that interfacial potassium is critical to maintain thermal stability of the anatase phase up to 900 °C. In addition, the deposition of potassium results in a negatively charged TiO 2 nanowhisker surface, which favors specific adsorption of methylene blue molecules and significantly improves SERS performance via the electrostatic adsorption effect.

Publication DOI: https://doi.org/10.1016/j.cjche.2019.10.003
Divisions: College of Engineering & Physical Sciences > School of Infrastructure and Sustainable Engineering > Chemical Engineering & Applied Chemistry
College of Engineering & Physical Sciences > Aston Institute of Materials Research (AIMR)
College of Engineering & Physical Sciences
Additional Information: © 2019, Elsevier. Licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International http://creativecommons.org/licenses/by-nc-nd/4.0/ Funding: Natural Science Foundation of China (21878143, 21476106, and 21838004), Joint Re-search Fund for Overseas Chinese Scholars and Scholars in Hong Kong and Macao Young Scholars (21729601), the fund of State Key Laboratory of Materials-Oriented Chemical Engineering (ZK201702, KL16-01), the Priority Academic Program Development of Jiangsu Higher Education Institutions (PAPD), the U.S. National Science Foundation (NSF) Grant No. CHE-1710102.
Uncontrolled Keywords: SERS,TiO nanowhisker,potassium induced,Environmental Engineering,Biochemistry,Chemistry(all),Chemical Engineering(all)
Full Text Link:
Related URLs: https://linking ... 004954119308821 (Publisher URL)
http://www.scop ... tnerID=8YFLogxK (Scopus URL)
PURE Output Type: Article
Published Date: 2019-10-25
Published Online Date: 2019-10-25
Accepted Date: 2019-10-17
Authors: Pan, Fan
Zhou, Guobing
Huang, Liangliang
Li, Wei (ORCID Profile 0000-0003-4036-467X)
Lin, Mingshen
Liu, Chang

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