The pyrolysis of zeolitic imidazolate frameworks (ZIFs) is becoming a popular approach for the synthesis of catalysts comprising porphyrin-like metal single atom catalysts (SACs) on N-doped carbons (M-N-C). Understanding the structural evolution of M-N-C as a function of ZIF pyrolysis temperature is important for realizing high performance catalysts. Herein, we report a detailed investigation of the evolution of Zn single atom catalyst sites during the pyrolysis of ZIF-8 at temperatures ranging from 500 to 900 °C. Results from Zn L-edge and Zn K-edge X-ray absorption spectroscopy studies reveal that tetrahedral ZnN₄ centers in ZIF-8 transform to porphyrin-like ZnN₄ centers supported on N-doped carbon at temperatures as low as 600 °C. As the pyrolysis temperature increased in the range 600–900 °C, the Zn atoms moved closer to the N₄ coordination plane. This subtle geometry change in the ZnN₄ sites alters the electron density on the Zn atoms (formally Zn²⁺), strongly impacting the catalytic performance for the peroxidase-like decomposition of H₂O₂. The catalyst obtained at 800 °C (Zn-N-C-800) offered the best performance for H₂O₂ decomposition. This work provides valuable new insights about the evolution of porphyrin-like single metal sites on N-doped carbons from ZIF precursors and the factors influencing SAC activity.

沸石咪唑酯骨架 (ZIF) 的热解正在成为一种流行的合成催化剂的方法，该催化剂包含在 N 掺杂碳 (MNC) 上的卟啉类金属单原子催化剂 (SAC)。了解 MNC 的结构演变作为 ZIF 热解温度的函数对于实现高性能催化剂很重要。在此，我们报告了 ZIF-8 在 500 至 900 °C 温度范围内热解过程中 Zn 单原子催化剂位点演变的详细研究。Zn L-edge 和 Zn K-edge X 射线吸收光谱研究结果表明，ZIF-8 中的四面体 ZnN ₄中心转变为卟啉类 ZnN ₄中心在低至 600 °C 的温度下支撑在 N 掺杂碳上。_{随着热解温度在 600–900 °C 范围内升高，Zn 原子向 N 4}配位平面靠拢。_{ZnN 4}位点的这种微妙的几何变化改变了 Zn 原子（正式为 Zn ²⁺）上的电子密度，强烈影响了 H ₂ O ₂类过氧化物酶分解的催化性能。_{在 800 °C 下获得的催化剂 (Zn-NC-800) 为 H 2} O ₂提供了最佳性能分解。这项工作为 ZIF 前驱体 N 掺杂碳上类卟啉单金属位点的演变以及影响 SAC 活性的因素提供了有价值的新见解。