Abstract

Identification of the real catalytic site in CO₂ reduction reaction (CO₂RR) is critical for the rational design of catalysts and the understanding of reactive mechanisms. In this study, the catalytic activity of pyridine-containing materials was for the first time structurally demonstrated in CO₂RR by crystalline supramolecular coordination compounds model system. The system consists of three stable supramolecular coordination compounds (Ni-TPYP, Ni-TPYP-1 and Ni-TPP) with different numbers (4, 2 and 0) of active pyridine groups (i.e. uncoordinated pyridine nitrogen atoms). The electrocatalytic test results show that with the decrease of the number of active pyridine groups, the CO₂RR performance is gradually reduced, mainly showing the reduction of highest FE_CO (99.8%, 83.7% and 25.6%, respectively). The crystallographic, experimental and theoretical evidences prove that the CO₂RR activity is more likely derived from uncoordinated pyridine nitrogen than the electrocatalytic inert metal nickel in porphyrin center. This work serves as an important case study for the identification of electrocatalytic activity of pyridine-containing materials in CO₂RR by simple supramolecular model system.

中文翻译：

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稳定超分子结构体系中战略催化位点分布识别CO2电还原活性来源

摘要

确定 CO ₂还原反应 (CO ₂ RR)中的真实催化位点对于合理设计催化剂和理解反应机制至关重要。在这项研究中，含吡啶材料的催化活性首次通过结晶超分子配位化合物模型系统在 CO ₂ RR 中得到结构证明。该系统由三种稳定的超分子配位化合物（Ni-TPYP、Ni-TPYP-1 和 Ni-TPP）组成，具有不同数量（4、2 和 0）的活性吡啶基团（即未配位的吡啶氮原子）。电催化试验结果表明，随着活性吡啶基团数量的减少，CO ₂RR性能逐渐降低，主要表现为最高的FE _CO降低（分别为99.8%、83.7%和25.6%）。晶体学、实验和理论证据证​​明，与卟啉中心的电催化惰性金属镍相比，CO ₂ RR 活性更可能来自未配位的吡啶氮。这项工作是通过简单的超分子模型系统鉴定含吡啶材料在 CO ₂ RR 中的电催化活性的重要案例研究。