摘要对于质子交换膜燃料电池（PEMFC），阴极的氧还原反应成为控制燃料电池性 能的主要因素。最近研究表明,石墨烯因超高比表面积、良好的电子导电性及丰富的 掺杂特性近年来在燃料电池催化剂方面表现出许多潜在的应用价值。基于此，本文探 索了不同元素掺杂的石墨烯对催化氧气还原反应的影响。石墨烯本身并不具备催化活 性，但是可以通过金属元素和非金属元素掺杂，使其功能化，进而具有良好的催化能 力。我们使用 Material Studio 软件搭建了石墨烯模型，并以此为基础对其进行掺杂（掺 杂金属：Pt、Au、Ni；掺杂非金属：Si、B、N），采用第一性原理的密度泛函理论， 对掺杂石墨烯作为 ORR 催化剂进行了系统的分析。通过分析氧气还原反应中间产物 的吸附能和反应过程中发生的能量变化，寻找符合吸附能不太强也不太弱的催化剂， 我们发现了 Au 掺杂石墨烯符合这一要求。除了吸附能，还需要考虑氧气还原反应中 热力学能垒。在 1。23 V 的高电势下，Au 掺杂石墨烯具有较低的热力学能垒，这表明 其只需要提供较低的能量，就能促使氧气还原反应的进行。最后，为了表征其物理本 质，我们分析了氧气还原反应的中间产物的电荷数以及掺杂金属元素的 d 带和掺杂非 金属元素的 p 带，从电子的角度解释了吸附现象。本文通过对石墨烯的掺杂，实现了 石墨烯的功能化，并表明掺 Au 石墨烯催化剂作为未来燃料电池阴极催化剂具有很大 的潜力。81362
毕业论文关键词：密度泛函理论；氧气还原反应；质子交换膜燃料电池；石墨烯
Abstract For the proton exchange membrane fuel cell (PEMFC), the oxygen reduction reaction of the cathode is the main factor to control the performance of the fuel cell。 In recent years, many studies have shown that graphene has shown a lot of potential applications in fuel cell catalysts due to its high specific surface area, good electronic conductivity and rich doping characteristics。 Here, this paper explores the effect of different element doped graphene on the catalytic oxygen reduction reaction。 Through the metal element and nonmetal doping, make it functional, and then have a good catalytic ability。 Graphene itself does not have catalytic activity。 But it can be functionalized by mean of the metal and nonmetal doping and possessed the superior ORR activity。 We use Studio Material software to build the graphene model, and use it as a basis for doping(Doped metal: Pt、Au、 Ni; Doped nonmetal:)。 By using the density functional theory of the first principle, we
systematic study the doped graphene as ORR catalyst。 By calculating the adsorption energy of ORR intermediate, we find that Au doped graphene catalyst possess the suitable adsorption ability。 Since the ORR catalyst must activate the O2 molecule and remove the oxide adsorbates, the adsorption energy of the optimal catalysts cannot be too strong or too weak。 Therefore, the Au doped graphene is expected to be good ORR catalyst。 Besides the adsorption energy, the thermodynamic energy barriers of the ORR steps are considered。 At the potential of 1。23 V, the Au doped graphene has the lowest thermodynamic energy barrier among the other functional BN。 This shows that it only needs to provide lower energy to promote the oxygen reduction reaction。 Finally, in order to understand the underlying mechanism, the Mulliken charge of ORR intermediates, the d-density of states of the metal element and the p-density of states of the nonmetal element have been analyzed。 From the Mulliken, it is observed that the more the electron transfer and the higher the d band(for metal doping) toward the Fermi energy makes the larger the adsorption energy。 The electronic analysis is consistent with the aforementioned results。 In 质子交换膜燃料电池催化剂组件graphene催化剂设计:http://www.youerw.com/huaxue/lunwen_95048.html