减少后的FeN环境:对旋转状态,光谱性质和活性物种的计算分析
Charlotte Gallenkamp1, Ulrike I Kramm2, Vera Krewald1
1Theoretische Chemie, Technische Universität Darmstadt, Peter-Grünberg-Str. 4, 64287 Darmstadt, Germany.
JACS Au
|April 1, 2024
概括
催化剂中的FeN4位点是氧气减少的关键. 本研究使用模型复合物和DFT来展示联结体场强度如何影响光谱性质,帮助检测催化中间体.
科学领域:
- 电化学 电化学 电化学
- 催化剂是一种催化剂.
- 计算化学计算化学
背景情况:
- 铁碳 (FeNC) 催化剂是燃料电池中金的有希望的替代品,对于氧气还原反应至关重要.
- 由于合成杂质,无形FeNC催化剂中活性FeN4位点的确切结构尚不清楚.
- 了解FeN4位点行为和光谱特征对于催化剂开发至关重要.
研究的目的:
- 为了研究Pyrrolic和PyridinicFeN4站点的电子结构和光谱特性.
- 为了预测光谱数据 (Mössbauer,UV-vis,NRV) 使用密度函数理论 (DFT) 对模型复合体.
- 在电化学条件下与可观测的光谱变化相关联联体场强度.
主要方法:
- 利用密度函数理论 (DFT) 建模了两个FeN4环境:pyrrolic ([Fe(TPP) Cl]) 和pyridinic ([Fe(phen2N2) Cl]).
- 为模型复合体计算预测的Mössbauer,UV-vis和NRV光谱数据.
- 多样化的轴联体,以评估对微小化学变化的敏感性和联体场强度差异.
主要成果:
- 在pyrrolic和pyridinic FeN4位点中的不同联结体场强度导致不同的自旋基态.
- 这些自旋状态的差异导致了独特而明显的Mössbauer光谱性质.
- 在操作条件下,与的捐赠者相比,的捐赠者 (较弱的场) 预计在操作条件下会显示出更明显的光谱变化.
结论:
- 在FeN4位点中较弱的配体场提高了在in situ和operando实验中催化中间体的检测能力.
- 以 DFT 预测为指导的光谱学方法,可以区分烯酸和烯酸 FeN4 环境.
- 这项工作为表征FeNC催化剂中的活性位点和优化其性能提供了基础.
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