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.

中文翻译：

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作为超灵敏表面增强拉曼光谱基底的银纳米粒子装饰的 α-Fe 2 O 3 纳米薄片的简易制造

尽管在设计贵金属纳米粒子聚集体/组件作为表面增强拉曼光谱 (SERS) 基底方面取得了很大进展，但越来越多的研究兴趣集中在制造分层纳米结构以获得优异的 SERS 性能。在这里，我们报告了银纳米粒子 (AgNPs) 在垂直和密集生长的 α-Fe2O3 纳米薄片 (NFs) 上作为 SERS 活性基材的有效装饰。通过在 450°C 下对 Fe 箔进行热退火以生长 α-Fe2O3 NFs 并将 AgNPs 化学沉积到 α-Fe2O3 NFs 上来制备 SERS 基板，具有优异的粒径和密度控制能力。AgNP 修饰的 α-Fe2O3 NFs 提供高密度热点并表现出高 SERS 性能，增强因子为 8.1 × 106。α-Fe2O3 纳米结构的整合用作特定分析物（如有毒砷）的内标和选择性结合剂。该底物成功用于砷的定量检测，具有空间均匀性（相对标准偏差，RSD，8.8%）和良好的重现性（RSD，9.7%）。集成到 SERS 基底上的 α-Fe2O3 的拉曼信号被用作内标，这显着提高了重现性。该底物对砷的检测表现出高灵敏度，检测限低至 1.5 μg L-1，远低于 WHO 设定的允许限值（10 μg L-1）。此外，SERS 底物在测定环境水体中的砷方面表现出优异的实用性和选择性，这对环境和人类健康保护具有重要意义。