Wang Junmei, Tian Qingkun, Ruda Harry E, Chen Li, Yang Maoyou, Song Yujun
Center for Modern Physics Technology, School of Mathematics and Physics, University of Science and Technology Beijing, Beijing 100083, China.
Shandong Key Laboratory of Optoelectronic Sensing Technologies/National-Local Joint Engineering Laboratory for Energy and Environment Fiber Smart Sensing Technologies, International School for Optoelectronic Engineering, Qilu University of Technology (Shandong Academy of Sciences), Jinan 250353, China.
Nanomaterials (Basel). 2025 Aug 1;15(15):1185. doi: 10.3390/nano15151185.
Surface and sub-surface atomic configurations are critical for catalysis as they host the active sites governing electrochemical processes. This study employs density functional theory (DFT) calculations and Monte Carlo simulations combined with the cluster-expansion approach to investigate atom distribution and Pt segregation in Pt-Fe alloys across varying Pt/Fe ratios. Our simulations reveal a strong tendency for Pt atoms to segregate to the surface layer while Fe atoms enrich the sub-surface region. Crucially, the calculations predict the stability of a periodic PtFe alloy surface model, characterized by specific defect structures, at low platinum content and low annealing temperatures. Electronic structure analysis indicates that forming this PtFe surface alloy lowers the d-band center of Pt atoms, weakening CO adsorption and thereby enhancing resistance to CO poisoning. Although defect-induced strains can modulate the d-band center, crystal orbital Hamilton population (COHP) analysis confirms that such strains generally strengthen Pt-CO interactions. Therefore, the theoretical design of PtFe alloy surfaces and controlling defect density are predicted to be effective strategies for enhancing catalyst resistance to CO poisoning. This work highlights the advantages of periodic PtFe surface models for anti-CO poisoning and provides computational guidance for designing efficient Pt-based electrocatalysts.
表面和次表面原子构型对于催化作用至关重要，因为它们承载着控制电化学过程的活性位点。本研究采用密度泛函理论（DFT）计算和蒙特卡罗模拟，并结合团簇展开方法，来研究不同Pt/Fe比例下Pt-Fe合金中的原子分布和Pt偏析。我们的模拟结果表明，Pt原子有强烈的偏析到表面层的趋势，而Fe原子则富集在次表面区域。至关重要的是，计算预测了在低铂含量和低退火温度下，具有特定缺陷结构的周期性PtFe合金表面模型的稳定性。电子结构分析表明，形成这种PtFe表面合金会降低Pt原子的d带中心，减弱CO吸附，从而增强对CO中毒的抗性。尽管缺陷诱导的应变可以调节d带中心，但晶体轨道哈密顿布居（COHP）分析证实，这种应变通常会加强Pt-CO相互作用。因此，PtFe合金表面的理论设计和控制缺陷密度预计将是增强催化剂抗CO中毒能力的有效策略。这项工作突出了周期性PtFe表面模型对于抗CO中毒的优势，并为设计高效的Pt基电催化剂提供了计算指导。
