In this work, the detailed oxygen reduction reaction (ORR) catalytic performance of M-N_4−xO_x (M = Fe, Co, and Ni; x =1−4) has been explored via the detailed density functional theory method. The results suggest that the formation energy of M-N_4−xO_x shows a good linear relationship with the number of doped O atoms. The adsorption manner of O₂ on M-N_4−xO_x changed from end-on (x = 1 and 2) to side-on (x = 3 and 4), and the adsorption strength gradually increased. Based on the results for binding strength of ORR intermediates and the Gibbs free energy of ORR steps on the studied catalysts, we screened out two highly active ORR catalysts, namely Co-N₃O₁ and Ni-N₂O₂, which possess very small overpotentials of 0.27 and 0.32 V, respectively. Such activities are higher than the precious Pt catalyst. Electronic structure analysis reveals one of the reasons for the higher activity of Co-N₃O₁ and Ni-N₂O₂ is that they have small energy gaps and moderate highest occupied molecular orbital energy levels. Furthermore, the results of the density of states reveal that the O doping can improve the electronic structure of the original catalyst to tune the adsorption of the ORR intermediates.

在这项工作中，通过详细的密度泛函理论方法探索了MN _{4− x} O _x（M = Fe，Co和Ni; x = 1-4）的详细的氧还原反应（ORR）催化性能。结果表明，MN _{4- x} O _x的形成能与掺杂的O原子数呈良好的线性关系。O ₂在MN _{4- x} O _x上的吸附方式从头到尾（x= 1和2）到侧面（x = 3和4），吸附强度逐渐增加。基于ORR中间体的结合强度和ORR步骤在研究的催化剂上的吉布斯自由能的结果，我们筛选出了两种高活性ORR催化剂，即Co-N ₃ O ₁和Ni-N ₂ O ₂，它们具有小过电位分别为0.27和0.32V。这样的活性高于珍贵的Pt催化剂。电子结构分析揭示了Co-N ₃ O ₁和Ni-N ₂ O ₂活性较高的原因之一它们具有小的能隙和中等的最高占据分子轨道能级。此外，状态密度的结果表明，O掺杂可以改善原始催化剂的电子结构，以调节ORR中间体的吸附。