Aghili Maryam, Hogan Benjamin T, Chamberland Joshua P, Barz Dominik P J, Docoslis Aristides
Department of Chemical Engineering, Queen's University, K7L 3N6 Kingston, Ontario, Canada.
ACS Omega. 2025 Apr 29;10(18):19175-19188. doi: 10.1021/acsomega.5c02124. eCollection 2025 May 13.
Surface-enhanced Raman scattering (SERS) pushes the boundaries of Raman spectroscopy as an analytical technique, allowing improved sensitivity and high discriminatory ability in analyte detection. Here, we introduce a SERS substrate using reduced graphene oxide aerogels as scaffolds. Reduced graphene oxide aerogels are hydrophobic, electrically conductive, and easily formable, providing a versatile platform for silver dendritic nanostructure growth via electrochemical deposition. We show that the electrochemical growth conditions (applied voltage, reduction time) have a significant effect on both the morphology and coverage of the silver nanostructures, which in turn have a strong effect on the SERS performance of the substrate. The importance of Ag dendrite morphology to the SERS substrate's performance is also confirmed by finite-difference time-domain simulations. Under silver growth conditions of 10 V applied voltage at 10 Hz for 120 min, we obtained a limit of detection of 3.16 × 10 ppm for thiram, which is lower than the testing requirements set by food and environmental regulatory agencies. Moreover, the substrates showed high silver coverage (85.6%), reproducibility (relative standard deviation ∼6% for substrates produced under the same conditions), and relative stability (∼20% change) of the obtained signal over one month. In view of their SERS capabilities and relative ease of preparation, we consider this new class of substrates a strong candidate for meeting detection and quantification challenges for a broad spectrum of analytes.
表面增强拉曼散射（SERS）作为一种分析技术拓展了拉曼光谱的边界，在分析物检测中具有更高的灵敏度和更强的鉴别能力。在此，我们介绍一种以还原氧化石墨烯气凝胶为支架的SERS基底。还原氧化石墨烯气凝胶具有疏水性、导电性且易于成型，为通过电化学沉积生长银树枝状纳米结构提供了一个通用平台。我们表明，电化学生长条件（施加电压、还原时间）对银纳米结构的形态和覆盖率都有显著影响，进而对基底的SERS性能有强烈影响。时域有限差分模拟也证实了银树枝状形态对SERS基底性能的重要性。在10 V施加电压、10 Hz频率下还原120分钟的银生长条件下，我们获得了福美双的检测限为3.16×10 ppm，低于食品和环境监管机构设定的测试要求。此外，基底显示出高银覆盖率（85.6%）、可重复性（相同条件下制备的基底相对标准偏差约为6%）以及在一个月内获得的信号具有相对稳定性（变化约20%）。鉴于其SERS能力和相对易于制备的特点，我们认为这类新型基底是应对广泛分析物检测和定量挑战的有力候选者。
