In-situ ECSTM investigation of H_2O_2 production in cobalt—porphyrin-catalyzed oxygen reduction reaction
In-situ ECSTM investigation of H_2O_2 production in cobalt—porphyrin-catalyzed oxygen reduction reaction
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DOI：
10.1007/s11426-022-1465-8
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发表时间：
2022-12
期刊：
影响因子：
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通讯作者：
Ya‐Chen Feng;Xiangfeug Wang;Zhenfeng Yi;Yu-Qi Wang;Hui-Juan Yan;Dong Wang
中科院分区：
文献类型：
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作者：
Ya‐Chen Feng;Xiangfeug Wang;Zhenfeng Yi;Yu-Qi Wang;Hui-Juan Yan;Dong Wang
采用电化学扫描隧道显微镜（ECSTM）在分子水平上对5，10，15，20-四（4-甲氧基苯基）-21H，23H-卟啉钴（II）（CoTMPP）催化的氧还原反应（ORR）中H2 O2的生成进行了原位研究.在STM图像中可以观察到OOH−在活性位点上的吸附，并发现其与电解质的pH值相关。通过对STM图像的定量分析，提取了CoTMPP-OOH−复合物形成的热力学参数。通过电化学测量可以揭示ORR的两个阶段，包括H2 O2的形成和在不同还原电位下H2 O2的进一步还原。In-situECSTM实验明确地确定了CoTMPP-OOH−络合物的形成及其还原和氧化过程。该研究为从分子水平上理解H2 O2的形成和转化过程提供了直接证据，有利于合理设计高效的氧化还原和H2 O2生产电催化剂。
We report thein-situinvestigation of the production of H2O2in 5,10,15,20-tetra(4-methoxyphenyl)-21H,23H-porphyrin cobalt(II) (CoTMPP)-catalyzed oxygen reduction reaction (ORR) in neutral electrolytes by electrochemical scanning tunneling microscopy (ECSTM) at the molecular scale. The adsorption of OOH−on active sites can be observed in STM images and is found to be correlated with the pH value of the electrolyte. The thermodynamic parameters of the formation of CoTMPP—OOH−complex are extracted by the quantitative analysis of the STM images. Two stages of the ORR including the formation of H2O2and further reduction of H2O2at different reduction potentials can be revealed by electrochemical measurements.In-situECSTM experiments unambiguously identify the formation of the CoTMPP—OOH−complex as the high contrast species and its reduction and oxidation process. This work provides the direct evidence for understanding the formation and transformation process of H2O2at the molecular scale, which benefits the rational design of the high-efficiency electrocatalysts for ORR and H2O2production.