Pt(hkl)單晶表面CO電氧化過程原位拉曼光譜研究進展

在質(zhì)子交換膜燃料電池的研究中，陽極催化劑CO中毒的問題會導(dǎo)致燃料電池性能下降和壽命縮短。CO分子在Pt(hkl)單晶電極表面的吸附和電氧化是解決燃料電池催化劑Pt中毒機理的關(guān)鍵步驟。
In the research of proton exchange membrane fuel cells, the problem of anode catalyst CO poisoning can lead to a decrease in fuel cell performance and a shortened lifespan. The adsorption and electro oxidation of CO molecules on the surface of Pt (hkl) single crystal electrodes are key steps in solving the Pt poisoning mechanism of fuel cell catalysts.
在該工作中，李劍鋒教授課題組利用原位SHINERS光譜技術(shù)，獲得了Pt(111)和Pt(100)上頂位和橋位吸附的CO*分子的拉曼信號，而在Pt(110)表面僅觀察到頂位吸附的CO*分子。另一方面，在Pt(111)和Pt(100)表面CO電氧化過程中的氧化前峰區(qū)間，原位觀測到了OH*和COOH*物種形成和消失的直接光譜證據(jù)，并通過同位素取代實驗和密度泛函理論進行了驗證，說明OH*和COOH*物種的形成和吸附在CO分子的電氧化過程中起著至關(guān)重要的作用，并與CO電氧化過程中氧化前峰相關(guān)。
In this work, Professor Jianfeng Li's research group used in-situ SHINERS spectroscopy technology to obtain Raman signals of CO * molecules adsorbed at the top and bridge sites on Pt (111) and Pt (100), while only CO * molecules adsorbed at the top site were observed on the Pt (110) surface. On the other hand, direct spectral evidence of the formation and disappearance of OH * and COOH * species was observed in situ in the pre oxidation peak range of CO electro oxidation on Pt (111) and Pt (100) surfaces. This was verified through isotope substitution experiments and density functional theory, indicating that the formation and adsorption of OH * and COOH * species play a crucial role in the electro oxidation process of CO molecules and are correlated with the pre oxidation peak during CO electro oxidation.

 
在實驗結(jié)合理論的研究基礎(chǔ)上，提出了合理的CO電氧化過程。在高氯酸的CO飽和溶液中，吸附態(tài)的CO*通過L-H機理與吸附態(tài)的OH*經(jīng)由COOH*過程，COOH*分解產(chǎn)生CO2釋放到溶液中。相反，在Pt(110)單晶表面，獲得了不同的實驗現(xiàn)象，進一步結(jié)合吸附構(gòu)型和理論計算，解釋了其活性較差的原因。該工作系統(tǒng)地研究了Pt(hkl)單晶電極表面CO的吸附和電氧化過程，為抗毒化和高效催化劑的設(shè)計提供了新的視角。
On the basis of experimental and theoretical research, a reasonable CO electro oxidation process was proposed. In a CO saturated solution of perchloric acid, adsorbed CO * reacts with adsorbed OH * through the L-H mechanism via the COOH * process, resulting in the decomposition of COOH * and the release of CO2 into the solution. On the contrary, different experimental phenomena were observed on the surface of Pt (110) single crystal, and further combined with adsorption configuration and theoretical calculations, the reason for its poor activity was explained. This work systematically studied the adsorption and electro oxidation processes of CO on the surface of Pt (hkl) single crystal electrodes, providing a new perspective for the design of anti poisoning and efficient catalysts.

 
該工作的實驗部分主要由我院博士研究生蘇敏和董金超博士共同完成，理論計算部分由樂家波博士完成，博士生趙宇、楊偉民等參與了論文的研究工作和討論。該研究工作得到國家自然科學(xué)基金、國家重點研發(fā)計劃等的資助和支持。
The experimental part of this work was mainly completed by our doctoral students, Dr. Su Min and Dr. Dong Jinchao. The theoretical calculation part was completed by Dr. Le Jiabo, and doctoral students such as Zhao Yu and Yang Weimin participated in the research and discussion of the paper. This research work has received funding and support from the National Natural Science Foundation and the National Key Research and Development Program.