铂单晶表面CO电氧化反应的原位拉曼光谱研究

As an extremely important fundamental anode reaction in the field of fuel cells, the CO electrooxidation mechanism at platinum-based catalyst surfaces has been a focus of the electrochemical community for a long time. After many years of research, considerable advancements have been made in understanding its core mechanism. However, due to the lack of in situ spectral evidence of the critical intermediate species at Pt(hkl) single crystal surfaces, it is difficult to precisely determine the reaction mechanism of CO electrooxidation. That said, the invention of shell-isolated nanoparticle-enhanced Raman spectroscopy (SHINERS) provides an excellent in situ spectroscopic strategy for studying the CO electrooxidation catalytic reaction at atomically smooth single crystal surfaces..In this research project, the applicant will study adsorption and electrooxidation processes of CO molecules at Pt(hkl) surfaces using in situ electrochemical SHINERS, which has the advantages of exceptional surface selectivity and low wavenumber detection sensitivity. Through the systematic investigation of CO electrooxidation processes at Pt(hkl) surfaces under acidic and alkaline conditions, respectively, direct spectroscopic evidence of key intermediate species will be secured by comparing with different control experiments. Combined with isotope experiments and DFT theoretical simulation, detailed adsorption structures and states of different reaction intermediates at Pt(hkl) surfaces will be confirmed. We will further study different influencing factor effects, such as facet and anion effects, to further understand the mechanism of CO electrooxidation and provide strong fundamental and theoretical support and guidance for the design and synthesis of high-efficiency CO electrooxidation catalysts.

在燃料电池研究中，铂基催化剂表面的CO电氧化过程是一个非常重要的基础反应。但由于在具有确定表面结构的单晶界面缺少该反应关键中间物种充足的原位光谱证据，人们还无法确定其具体的反应机理。壳层隔绝纳米粒子增强拉曼光谱（SHINERS）的出现为研究原子级平滑的单晶界面上的电催化反应提供了一种很好的原位光谱技术。在本项目中，申请人拟利用电化学SHINERS光谱技术原位研究Pt(hkl)单晶界面CO分子的吸附和电氧化过程，充分发挥拉曼光谱表面选律和低波数区域检测优势，原位监测CO电氧化反应过程。通过对酸、碱条件下Pt(hkl)单晶界面CO电氧化过程的系统考察，以及对关键中间物种原位光谱证据的有效捕获、确认，具体分析CO电氧化反应过程。同时对不同的影响因素进行系统考察及同位素实验确认，结合DFT理论模拟，揭示Pt(hkl)单晶界面CO电氧化机理，为高效CO电氧化催化剂的设计合成提供直接的理论指导。

本项目通过优化增强基底、调控壳层厚度、改进弱耦合单晶界面拉曼信号采集模式，成功获得不同单晶表面CO电氧化反应等催化反应在不同条件下关键中间物种的直接光谱证据，并结合同位素取代实验，确认相关中间物种的归属。并结合理论计算，揭示电催化反应机理和构效关系。与此同时，申请人进一步发展双功能核壳纳米结构增强拉曼光谱技术，并将研究工作拓展至其他重要反应体系的原位光谱研究，取得多项实质性进展。经过三年的研究，顺利达到预期目标。在项目执行期间，相关工作共发表论文12篇，其中包括Energy. Environ. Sci.、J. Am. Chem. Soc.、Angew. Chem. Int. Ed.（4篇）、Nano. Lett.、Nano Res.、J. Catal.、Anal. Chem，并在Annu. Rev. Phys. Chem.、J. Phys. Chem. C撰写综述论文。申请发明专利1件，联合培养硕博博士后研究生4人。