Facile fabrication of silver nanoparticle decorated α-Fe2O3 nanoflakes as ultrasensitive surface-enhanced Raman spectroscopy substrates

Deribachew Bekana; Rui Liu; Shasha Li; Yujian Lai; Jing-Fu Liu

doi:10.1016/j.aca.2017.12.003

Facile fabrication of silver nanoparticle decorated α-Fe₂O₃ nanoflakes as ultrasensitive surface-enhanced Raman spectroscopy substrates

Anal Chim Acta. 2018 May 2:1006:74-82. doi: 10.1016/j.aca.2017.12.003. Epub 2017 Dec 19.

Authors

Deribachew Bekana¹, Rui Liu², Shasha Li¹, Yujian Lai¹, Jing-Fu Liu³

Affiliations

¹ State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, P. O. Box 2871, Beijing 100085, China; University of Chinese Academy of Sciences, Beijing 100049, China.
² State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, P. O. Box 2871, Beijing 100085, China.
³ State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, P. O. Box 2871, Beijing 100085, China; University of Chinese Academy of Sciences, Beijing 100049, China. Electronic address: jfliu@rcees.ac.cn.

PMID: 30016266
DOI: 10.1016/j.aca.2017.12.003

Abstract

Although great progress has been made on designing noble metal nanoparticle aggregates/assemblies as surface-enhanced Raman spectroscopy (SERS) substrates, an ever increasing research interest has focused on fabrication of hierarchical nanostructures for superior SERS performance. Here, we report effective decoration of silver nanoparticles (AgNPs) onto vertically and densely grown α-Fe₂O₃ nanoflakes (NFs) as SERS active substrates. The SERS substrate was prepared by thermally annealing Fe foil at 450 °C to grow α-Fe₂O₃ NFs and electroless deposition of AgNPs onto α-Fe₂O₃ NFs, with excellent ability to control the particle size and density. The AgNP-decorated α-Fe₂O₃ NFs offer high density hot spots and exhibited high SERS performance with enhancement factor of 8.1 × 10⁶. Integration of α-Fe₂O₃ nanostructure functions as intrinsic internal standard and selective binder for specific analytes like the toxic arsenic. The substrate was successfully used for quantitative detection of arsenic with spatial uniformity (relative standard deviation, RSD, 8.8%) and good reproducibility (RSD, 9.7%). The Raman signal of α-Fe₂O₃ integrated to the SERS substrate was utilized as internal standard which significantly improves reproducibility. The substrate exhibited a high sensitivity for arsenic detection with a limit of detection down to 1.5 μg L^-1, which is much lower than permissible limit (10 μg L^-1) set by the WHO. Moreover, the SERS substrates showed excellent practicability and selectivity for determination of arsenic in environmental waters which is valuable for environmental and human health protection.

Keywords: Arsenic detection; Fe foil; Intrinsic internal standard; Silver nanoparticles; Surface-enhanced Raman spectroscopy; α-Fe(2)O(3) nanoflakes.