化学
过氧化氢
催化作用
金属
过渡金属
氮气
碳纤维
共价键
氢
无机化学
过氧化物
光化学
组合化学
有机化学
材料科学
复合数
复合材料
作者
Chang Liu,Hao Li,Fei Liu,Junsheng Chen,Zixun Yu,Ziwen Yuan,Chaojun Wang,Huiling Zheng,Graeme Henkelman,Li Wei,Yuan Chen
摘要
Metal–nitrogen–carbon (M–N–C) single-atom catalysts (SACs) show high catalytic activity for many important chemical reactions. However, an understanding of their intrinsic catalytic activity remains ambiguous because of the lack of well-defined atomic structure control in current M–N–C SACs. Here, we use covalent organic framework SACs with an identical metal coordination environment as model catalysts to elucidate the intrinsic catalytic activity of various metal centers in M–N–C SACs. A pH-universal activity trend is discovered among six 3d transition metals for hydrogen peroxide (H2O2) synthesis, with Co having the highest catalytic activity. Using density functional calculations to access a total of 18 metal species, we demonstrate that the difference in the binding energy of O2* and HOOH* intermediates (EO2* – EHOOH*) on single metal centers is a reliable thermodynamic descriptor to predict the catalytic activity of the metal centers. The predicted high activity of Ir centers from the descriptor is further validated experimentally. This work suggests a class of structurally defined model catalysts and clear mechanistic principles for metal centers of M–N–C SACs in H2O2 synthesis, which may be further extendable to other reactions.
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