Electrocatalytic Oxygen Reduction by Cu Complexes of Tripeptide Derivatives of Glutathione
Electrocatalytic Oxygen Reduction by Cu Complexes of Tripeptide Derivatives of Glutathione
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DOI：
10.1021/acs.jpcc.3c02471
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发表时间：
2023-07
期刊：
影响因子：
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通讯作者：
Profulla Mondol;M. Hassani;M. J. Tucker;Christopher J. Barile
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文献类型：
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作者：
Profulla Mondol;M. Hassani;M. J. Tucker;Christopher J. Barile
氧气还原反应（ORR）的缓慢是燃料电池商业化的最大挑战。Cu基ORR催化剂是有前景的Pt的非贵金属替代物。本研究合成了四种不同的三肽Cu ~（2+）配合物（Cu-GSHAmide，Cu-NCG，Cu-ECG，Cu-QCG），并分析了它们的电催化活性与理化性质的关系。旋转环-盘电极实验表明，催化电流密度和选择性作为pH和肽身份的函数变化很大。通过傅里叶变换红外光谱，我们描述了研究的肽与相应的Cu 2+配合物的沿着的分子间力的性质。该分析使我们能够量化ORR电催化剂中肽聚集的程度。结合Cu 2 +-肽结合常数，我们开发的模型，准确地预测肽聚集如何决定催化剂的电流密度和选择性的四电子还原O2水。这些模型表明具有相对强的结合常数和弱肽聚集的Cu 2 +-肽ORR电催化剂表现出增加的选择性和增强的动力学。这一中心发现强调了一套重要的设计规则，为未来的高性能铜ORR电催化剂的发展。
The sluggishness of the O2reduction reaction (ORR) is the most significant challenge to fuel cell commercialization. Cu-based ORR catalysts are promising non-precious metal alternatives to Pt. In this study, we synthesize four different Cu2+complexes of tripeptides (Cu–GSHAmide, Cu–NCG, Cu–ECG, and Cu–QCG) and analyze the relationships between their electrocatalytic activities and physicochemical properties. Rotating ring-disk electrode experiments indicate that the catalytic current densities and selectivities vary widely as a function of pH and peptide identity. Through Fourier transform infrared spectroscopy, we describe the nature of the intermolecular forces between the peptides studied along with those of the corresponding Cu2+complexes. This analysis allows us to quantify the degree of peptide aggregation in the ORR electrocatalysts. Combined with the Cu2+–peptide binding constants, we develop models that accurately predict how peptide aggregation dictates catalyst current density and selectivity for the four-electron reduction of O2to water. These models indicate that Cu2+–peptide ORR electrocatalysts with relatively strong binding constants and weak peptide aggregation exhibit increased selectivity and enhanced kinetics. This central finding highlights an important set of design rules for the development of future high-performance Cu ORR electrocatalysts.