AI 中文总结
该研究利用原位拉曼光谱，在铂纳米催化剂上发现氧还原反应产生的含氧吸附物具长寿命与滞后特性，突破了传统认知，揭示了实际催化剂表面吸附结构的复杂性。
AI 中文摘要
水相电催化会在催化剂表面生成含氧中间体。尽管已观测到单晶催化剂表面的中间体物种，但工业相关的纳米颗粒（NP）催化剂表面含氧物种的性质与演化仍大多未知。本文利用原位拉曼光谱，追踪了碱性介质中具有活性铂（Pt）表面的NP催化剂上含氧吸附物的形成及依赖电位的演化。通过对比氩气（Ar）与氧气（O₂）饱和电解质中的光谱特征，确定了氧还原反应（ORR）产生的三种关键中间体：吸附态OOH、OH及O₂。与中间体仅在催化反应期间存在的传统认知相反，本文发现这些含氧吸附物具有长寿命和滞后特性，甚至在ORR终止后仍会留存。该吸附物保留效应对表面氧化态及电解质阳离子（K⁺与Li⁺）表现出适度依赖性，且可能因催化剂表面的异质性而加剧。研究结果凸显了实际催化剂表面吸附结构的复杂性，其往往超出模型单晶表面测量或模拟所捕捉的范围。
英文摘要
Aqueous electrocatalysis generates oxygenated intermediates at catalyst surfaces. While intermediate species on single-crystal catalysts have been observed, the nature and evolution of surface oxygenated species on industrially relevant nanoparticle (NP) catalysts remain largely unknown. Here, using in situ Raman spectroscopy, we tracked the formation and potential-dependent evolution of oxygenated adsorbates in alkaline media on NP catalysts with an active platinum (Pt) surface. By comparing spectroscopic features in Ar- vs O2-saturated electrolytes, we determined three key intermediates produced by the oxygen reduction reaction (ORR): adsorbed OOH, OH, and O2. In contrast to the conventional wisdom that intermediates exist only during catalytic reactions, we found these oxygenated adsorbates to be highly long-lived and hysteretic, and to persist even after the termination of ORR. This adsorbate-retention effect exhibits a modest dependence on the surface oxidation state and the electrolyte cations (K+ vs Li+), and is likely facilitated by the heterogeneous nature of the catalyst surface. The results highlight the complexity of surface adsorption structures on realistic catalysts, which often extends beyond that captured by measurements or simulations on model single-crystal surfaces.
