标题: 求助：为什么模仿一篇FeCo双金属单原子论文计算差分电荷密度时趋势与原文不一致 [打印本页] 作者Author: ComputationPawn 时间: 2022-11-16 20:35 标题: 求助：为什么模仿一篇FeCo双金属单原子论文计算差分电荷密度时趋势与原文不一致 我使用的是2019版本MS软件中的CASTEP模块，在模仿《Bi-functional electrocatalysis through synergetic coupling strategy of atomically dispersed Fe and Co active sites anchored on 3D nitrogen doped carbon sheets for Zn-air battery》这篇论文进行差分电荷密度进行计算时，出现了以下问题：
文中对于差分电荷密度的描述：The density functional theory (DFT) calculation studies were performed to explore the role of Co dopants and the synergistic effect between FeN4 and CoN4 for ORR [45–47]. The computational details are presented in Supporting Information and structure models were established (Fig. 6a). The A-FeCo@NCNs was used to study the effect of Co atom dopants in FeN4. In comparison, A-Fe@NCNs is obtained without introducing Co element and A-FeCo-NP@NCNs is built with Co metallic nanoparticles adjacent to FeN4. The differential charge density distributions of those structural models are showed in Figs. 6b and S13. Moreover, the Bader charge for metal atoms in FeN4, FeN4-CoN4, and FeN4-Co structures (Fig. S14) was obtained. Of note, the metal atoms (both Fe and Co) are electron donors, while the adjacent C/N atoms are electron acceptors. Fe atom in FeN4 loses 1.052 electrons, while Fe atom in FeN4-CoN4 loses 1.048 electrons, which indicates the increased electron density around Fe atom in FeN4-CoN4, agreeing well with the XPS results [48,49]. It is known that that higher electron density would be favorable for the adsorption and activation of O2 molecules and the high ORR activities of Fe single atom catalysts are mainly contributed by the enhanced electron density around Fe atoms [50]. Based on these results, it can be deduced that Fe and Co in the carbon framework will affect each electronic structure. Moreover, such synergetic effect will improve the activity towards ORR.