Li Jin, Zhang Qing-Ying, Yan Zhendong, Li Jian, Xia Xing-Hua
State Key Lab of Analytical Chemistry for Life Science, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210023, China.
College of Science, Nanjing Forestry University, Nanjing 210037, China.
Anal Chem. 2024 Dec 31;96(52):20382-20389. doi: 10.1021/acs.analchem.4c03711. Epub 2024 Dec 17.
Attenuated total reflectance surface-enhanced infrared absorption spectroscopy (ATR-SEIRAS) plays a crucial role in understanding the interfacial reaction mechanisms at the molecular level, achieving an enhancement factor (EF) of up to 10. However, when this technique is integrated with electrochemistry (EC-ATR-SEIRAS), the EF is significantly reduced by ten- to hundred-fold. Thus, understanding of the key parameters that contribute to the EF is of great importance in designing high-performance substrates and extending the application for EC-SEIRAS. In this study, we propose that the structure of the substrate for EC-ATR-SEIRAS consists of an enhancement unit (EU) supported on a conductivity unit (CU). The CU will screen the incident IR light reaching and interacting with the EU, resulting in a smaller EF as the CU thickness increases. Then, we introduce a strategy to optimize the performance of the EC-SEIRAS substrate by assembling a plasmonic antenna array as the EU that is supported on IR-transparent and conductive monolayer graphene as the CU. The established plasmon-enhanced EC-SEIRAS substrate demonstrates much higher IR enhancement, repeatability, and stability.
衰减全反射表面增强红外吸收光谱（ATR-SEIRAS）在分子水平上理解界面反应机制方面起着关键作用，实现了高达10的增强因子（EF）。然而，当该技术与电化学相结合（EC-ATR-SEIRAS）时，增强因子会显著降低至十分之一到百分之一。因此，了解影响增强因子的关键参数对于设计高性能基底和扩展EC-SEIRAS的应用至关重要。在本研究中，我们提出用于EC-ATR-SEIRAS的基底结构由支撑在导电单元（CU）上的增强单元（EU）组成。导电单元会屏蔽到达增强单元并与其相互作用的入射红外光，随着导电单元厚度增加，增强因子会变小。然后，我们引入一种策略，通过组装等离子体天线阵列作为增强单元，并将其支撑在红外透明且导电的单层石墨烯作为导电单元上，来优化EC-SEIRAS基底的性能。所建立的等离子体增强EC-SEIRAS基底表现出更高的红外增强、重复性和稳定性。
