Combination of spectroscopic techniques with electrochemistry is a promising way to elucidate electrocatalytic mechanisms at a molecular level. Surface-enhanced Raman spectroscopy (SERS) is a non-destructive, ultrasensitive fingerprint technique that can detect metal–adsorbate and metal oxide vibrations. However, it is hard to study nanocatalysts because of the morphology limitation of SERS. In this paper, core-shell-satellite nanostructures have been fabricated by assembling PtFe nanocatalysts on shell-isolated nanoparticles (SHINs). CO electrooxidation on these nanostructures was studied by in situ electrochemical shell-isolated nanoparticle-enhanced Raman spectroscopy (EC-SHINERS). The in situ spectroscopic results correlate well with the results obtained using cyclic voltammetry, and show that PtFe bimetallic nanocatalysts have improved CO electrooxidation activity. The in situ SHINERS studies also show that this improvement is the result of weaker CO adsorption on PtFe compared to Pt, as revealed by the red shift of the Raman band of the PtC stretching vibration on PtFe. This work demonstrates that this method is a powerful tool for in situ investigation of the electrocatalytic processes occurring on nanocatalysts and provides a better understanding of the reaction mechanisms.

光谱技术与电化学的结合是从分子水平阐明电催化机理的一种有前途的方法。表面增强拉曼光谱（SERS）是一种非破坏性的超灵敏指纹技术，可以检测金属吸附物和金属氧化物的振动。然而，由于SERS的形态学限制，难以研究纳米催化剂。在本文中，通过在壳分离的纳米颗粒（SHINs）上组装PtFe纳米催化剂，制备了核-壳-卫星纳米结构。通过原位电化学壳分离的纳米颗粒增强拉曼光谱（EC-SHINERS）研究了这些纳米结构上的CO电氧化。原位光谱结果与使用循环伏安法获得的结果密切相关，并表明PtFe双金属纳米催化剂具有改善的CO电氧化活性。原位SHINERS研究还表明，这种改善是由于与Pt相比，CO在PtFe上的吸附较弱，这是由Pt拉曼能带的红移所揭示的。C在PtFe上拉伸振动。这项工作表明，该方法是原位研究纳米催化剂上发生的电催化过程的有力工具，并且可以更好地理解反应机理。