【作者】 李静；

【导师】 戴黎明； 杨亦双；

【作者基本信息】 北京化工大学 ， 材料与化工（专业学位）， 2024， 硕士

【摘要】 相比于质子交换膜燃料电池,阴离子交换膜燃料电池（Anion Exchange Membrane Fuel Cell,AEMFC）因可以使用价格低廉的组件,以及阴极氧还原反应动力学快速可以使用非贵金属催化剂等优势,为降低燃料电池的成本并实现商业化应用提供了可能,但其阳极氢氧化反应（Hydrogen Oxidation Reaction,HOR）动力学缓慢,严重阻碍了AEMFC的实际应用。目前,Pt基材料仍为性能最优的HOR催化剂,但其存在成本昂贵以及稳定性不足等问题。为解决这些问题,本文围绕着高性能低铂催化剂的设计,通过碳缺陷诱导沉积具有高原子利用率的原子尺度铂以及碳载体调控策略,实现了催化剂质量活性的提升以及稳定性的增强。本文的主要内容和结论如下:（1）通过ZIF-8前驱体热解处理得到缺陷碳载体（Defective Carbon,DC）,并利用碳缺陷能够还原、锚定以及限制Pt纳米颗粒生长的能力,无电沉积形成具有强界面水结合能力的单原子位点,以及高质量活性的原子团簇位点,协同促进HOR动力学过程。测试结果表明,在50 m V过电位下,Pt _SA/Pt _AC-DC催化剂的质量归一化动力学电流密度达到2911.1 m A mg_PGM^-1,是商业Pt/C的6.5倍,表现出优异的HOR催化质量活性。此外,Pt _SA/Pt _AC-DC催化剂还表现出优于Pt/C催化剂的稳定性以及抗CO中毒能力。（2）进一步利用3d过渡金属（Fe、Co、Ni、Cr和Mn）掺杂调控缺陷碳载体,在ZIF-8制备过程中直接加入过渡金属盐原位生长得到M@ZIF-8,经过热解处理得到具有分散过渡金属单原子位点的缺陷碳载体(M_SA-DC)。通过X射线光电子能谱和X射线吸收近边结构分析表明,掺杂后的缺陷碳载体与Pt金属位点之间具有更强的电荷转移,金属–载体相互作用增强。稳定性测试结果表明,Pt _SA/Pt _AC-Ni _SA-DC催化剂于0.1 V恒定过电位下连续测试80 h仍保留63.4%的活性,以及在0～0.5 V的电位窗口内经过20000圈ADT测试后,半波电位仅增加3.3 m V,表现出优异的稳定性。此外,由于分散的Ni单原子位点与Pt金属位点之间的电荷转移,使得Pt位点d带中心下移,远离费米能级,中间体吸附强度减弱,所以表现出更高的活性以及抗CO中毒能力,其质量活性约为Pt/C的7.6倍,达到3440 m A mg_PGM^-1更多还原

【Abstract】 Compared with the proton exchange membrane fuel cell,the anion exchange membrane fuel cell（AEMFC）offers the possibility of reducing the cost of fuel cells and realizing commercial application due to the advantages of using inexpensive components and the fast kinetics of cathodic oxygen reduction reaction and the use of nonprecious metal catalysts,etc.However,the slow kinetics of Hydrogen Oxidation Reaction（HOR）at the anode has seriously hindered the practical application of AEMFC.Currently,Pt-based materials are still the HOR catalysts with optimal performance,but they suffer from the problems of expensive cost as well as insufficient stability.To solve these problems,this paper centers around the design of high-performance low-Pt catalysts,and the improvement of catalyst mass activity as well as the enhancement of stability is achieved through the carbon defect-induced deposition of atomic-scale Pt with high atom utilization as well as the carbon supports modulation strategy.The main contents and conclusions of this paper are as follows:（1）The defective carbon（DC）supports were obtained by pyrolysis treatment of ZIF-8 precursor,and the ability of carbon defects to reduce,anchor and restrict the growth of Pt nanoparticles was utilized for the electroless deposition of single-atom sites with strong interfacial water-binding ability to promote interfacial charge conduction,as well as high mass-active atom cluster sites,which can synergistically promote the HOR kinetic process.The test results show that the mass-normalized kinetic current density of Pt _SA/Pt _AC-DC reaches 2911.1 m A mg_PGM^-1,which is 6.5 times higher than that of the commercial Pt/C at 50 m V overpotential,and exhibits excellent HOR-catalyzed mass activity.In addition,the Pt _SA/Pt _AC-DC catalysts also exhibited superior stability to the Pt/C catalysts as well as resistance to CO poisoning.（2）The defective carbon supports were further modulated by doping with3d transition metals（Fe,Co,Ni,Cr,and Mn）,and M@ZIF-8 was obtained by directly adding transition metal salts to the in-situ growth during the preparation of ZIF-8,and the defective carbon supports(M_SA-DC)with dispersed transition metal single sites were obtained by pyrolysis treatment.Analysis by X-ray photoelectron spectroscopy and X-ray absorption near-edge structure shows that the doped defective carbon supports have stronger charge transfer with Pt metal sites and enhanced metal–support interaction.The stability test results showed that the Pt _SA/Pt _AC-Ni _SA-DC catalysts exhibited excellent stability by retaining 63.4%activity after continuous testing at a constant overpotential of0.1 V for 80 h,as well as an increase in half-wave potential by only 3.3 m V after 20,000 cycles of ADT within the potential window of 0～0.5 V.In addition,due to the charge transfer between the dispersed Ni monoatomic sites and the Pt metal sites,the d-band center of the Pt site is shifted downward away from the Fermi energy level,and the strength of intermediate adsorption is weakened,so that it exhibits higher activity and resistance to CO poisoning,and its mass activity is about 7.6 times of that of Pt/C,which reaches 3440 m A mg_PGM^-1.更多还原