中文摘要
PtFe/PdFe嵌入石墨烯的结构稳定性及其对CO的催化氧化性
直接甲醇燃料电池（DMFC）是一种很有发展潜力的能源，因为其燃料来源丰富，能量密度高，不造成环境污染。在所有的直接甲醇燃料电池阳极材料中，Pt及Pt族的金属是最好的电化学催化剂。Pt与一些特定的过渡金属结合可以减少催化剂的成本，并且提高纯Pt催化剂对CO中毒的抵抗能力。石墨烯因为其独特的电学性能，机械学以及热力学性能使其成为了负载金属纳米粒子的优良载体。在本论文中，我们使用密度泛函理论（DFT）方法对PtFe/PdFe嵌入石墨烯的几何稳定性及其对CO的催化氧化性能进行了研究。研究结果表明，向石墨烯中引入缺陷对掺杂的金属原子的性能有着极大程度的改善，缺陷石墨烯可以有效的绑定掺杂的金属原子，从而排除了金属原子的扩散或聚集的可能性。Pt (Pd) 和Fe原子可以代替石墨烯中的C原子。由于引入了Fe原子，可以有效的活化O2分子，增强对O2分子的吸附能力，缓解CO对Pt、Pd原子的毒化。PtFe/PdFe-graphene催化剂体系对CO的氧化反应机理Eley-Rideal (ER) 机理都优于Langmuir-Hinshelwood (LH) 机理。即单独的CO分子直接与预先吸附的O2分子，或通过表面活化的O2分子解离得到的O原子发生反应。此外，在PtFe-graphene和PdFe-graphene催化体系中，完整的CO氧化过程经过两步ER 反应：CO(gas) + O2(ads) → CO2(ads) + O(ads)和CO(gas) + O(ads) → CO2(ads)。我们的研究表明，PtFe/PdFe共同嵌入石墨烯中可以作为氧化CO的催化剂，并且在原子催化剂层面上探索了CO氧化反应的微观机理。
观看长津湖有感关键词：
密度泛函理论（DFT），Eley-Rideal机理，金属嵌入石墨烯，催化剂
Abstract
Geometric stability of PtFe/PdFe embedded graphene and
their catalytic activity for CO oxidation
The direct methanol fuel cell (DMFC) is considered as a promising power, becau of its abundant fuel source, high energy density and environment friendliness. Among all DMFC anode materials, Pt and Pt group metals are considered to be the best electrocatalyst. The co-operation of Pt with some specific transition metals can reduce the cost and improve the tolerance toward CO-poisoning of pure Pt catalysts. Graphene has been considered as one of the most promising candidate as the support for metal nanoparticles due to its fascinating electrical, mechanical and thermal properties originating from the two-dimensional honeycomb atomic structure. In this paper, the geometric stabilities of PtFe/PdFe atoms anchored in graphene sheet and catalytic oxidation CO properties were investigated using the density functional theory (DFT) method. The results show that introducin
g defects to graphene could efficiently promote its efficiency, the defects in graphene can effectively bind the doping metal atoms, and exclude the possibility of diffusion an aggregation of the embedded atoms. the Pt (Pd) and Fe atoms can instead of C atoms in graphene sheet. The diatomic (PtFe/PdFe) doping graphene can efficiently weaken the adsorption of CO to Pt or Pd atom, becau the Fe species located on the catalyst surface efficient activate O2 , which can alleviate the CO poisoning of catalyst. The CO oxidation by molecule O2 on PtFe- and PdFe-graphene studied next. The results show that the Eley-Rideal (ER) mechanism is expected over the Langmuir-Hinshelwood (LH) mechanism for CO oxidation on both PtFe- and PdFe-graphene. For the ER mechanism, the free-standing CO directly reacts with a preadsorbed O2molecule or atomic O generated through a surface motivated O2 dissociation. Further, the complete CO oxidation on PtFe- and PdFe-graphene are proceed via a two-step ER reaction: CO(gas)+ O2(ads) →CO2(ads) + O(ads) and CO(gas) + O(ads) → CO2(ads). Our results reveal that PtFe/PdFe common embedded in graphene can be ud as an catalyst for CO oxidation, and explore the
microscopic mechanism of the CO oxidation reaction on atomic-catalysts.
Keywords:
善念DFT, Eley-Rideal mechanism, Metal atoms embedded graphene, Catalys
目录
第1章绪论 (1)
1.1 引言 (1)
如何经营网店
玻璃分类1.2 Pt基二元催化剂 (1)
1.3 石墨烯 (3)
1.4 过渡金属掺杂石墨烯 (4)
豪车排名前十名1.5 本文研究的内容及研究意义 (5)
第2章理论基础与计算方法 (7)
2.1 引言 (7)
2.2 密度泛函理论 (8)
2.3 过渡态理论 (9)
2.3.1 传统过渡态理论 (10)
2.3.2 变分过渡态理论 (10)
2.4 势能面（Potential Energy Surface, PES） (11)
2.5 内禀反应坐标理论 (13)
2.6 基组 (14)
2.6.1 极小基组 (15)
2.6.2 分裂价键基组 (15)
2.6.3 极化基组 (16)
2.6.4 赝势基组 (16)
美人鱼岛2.7 计算软件 (17)
项羽虞姬2.7.1 计算软件介绍 (17)
2.7.2 Gaussian 09 软件包 (17)
第3章PtFe/PdFe镶嵌入石墨烯的结构稳定性及其对CO的催化氧化性 (18)
3.1 引言 (18)
3.2 计算方法 (19)
3.3 结果和讨论 (20)
3.3.1 PtFe-graphene和PdFe-graphene的几何结构、稳定性和
电子性质 (20)
3.3.2 O2在PtFe-graphene和PdFe-graphene上的吸附 (22)
3.3.3 CO在PtFe-graphene和PdFe-graphene上的吸附 (25)
3.3.4 CO氧化反应机理研究 (26)
3.4 结论 (30)
参考文献 (32)
wds无线桥接
作者简介及硕士期间所取得的科研成果 (42)
致谢 (43)
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