Synthesis and Electrocatalytic Activity of Ruthenium Cobalt Alloys toward Oxygen Reduction Reaction

质子交换膜燃料电池具有工作温度低、启动快、比功率高等优点，被认为是电动汽车等的首选能源。现有的燃料电池技术需要使用价格昂贵的铂基催化剂，且阴极氧还原反应的过电位较大，严重阻碍了其商业化进程。因此，有必要研究同时具有高氧还原活性和良好稳定性的非铂阴极催化剂。钌基催化剂具有良好的氧还原活性，但钌硒化合物催化剂的稳定性较差，钌用量大，而钌基合金催化剂中钌的用量可调整，但存在氧还原活性较差，合成所用的金属先驱体较昂贵，甚至有毒，难于得到纯相等问题。本论文采用较廉价的金属氯化物为原料，探索浸渍还原法并结合热处理制备高氧还原活性和高稳定性的碳载钌钴（铁）合金催化剂的方法，系统研究了钌/钴比例、催化剂载体、...Proton exchange membrane fuel cell (PEMFC) has been considered to be the preferred energy for electric vehicles due to its advantages of low working temperature, quick startup and high specific power density. Current technology in PEMFC usually requires the use of expansive platinum-based materials as catalysts. Furthermore, a large overpotential resulting from oxygen reduction reaction (ORR) at a...学位：工学硕士院系专业：材料学院_材料物理与化学学号：2072012115002

Synthesis and Properties of Platinum-based Nano-cactalysts of High Activity and Durability for Oxygen Reduction Reaction

成本和寿命是制约质子交换膜燃料电池（PEMFC）发展的两个重要问题。其中电池成本又可以通过延长使用寿命进行降低。因此，延长电池寿命是提升燃料电池整体性能的一个有效途径。氧还原反应(ORR)是燃料电池的阴极反应，由于其反应动力学迟缓，导致阴极极化严重。PEMFC工作中出现30%~40%的电压损失主要来自阴极ORR。与阳极氢气氧化相比，ORR需要更多的铂催化剂。因此提高阴极ORR催化剂的性能，尤其耐久性，是提升燃料电池的整体性能，降低燃料电池成本的重要途径。铂是目前最好的氧还原催化剂，鉴于铂的不可替代性，在近期及未来很长一段时间内，铂基催化剂仍将是质子交换膜燃料电池的主要催化剂。因此，研究和开发具...Cost and lifetime are two important issues restricting the development of proton exchange membrane fuel cell (PEMFC). Improving the durability of catalyst is an effective way to improve the overall performance of the fuel cell, since it can reduce the cost simultaneously. Oxygen reduction reaction (ORR) is the cathode reaction of PEMFC. The sluggish kinetics of ORR results in serious cathode polar...学位：理学博士院系专业：化学化工学院_物理化学(含化学物理)学号：2052009015333

基于ZIF-8衍生氮掺杂多孔碳的高稳定性氧还原催化剂

沸石咪唑脂框架8(ZIF-8),高温热解处理得到氮掺杂多孔碳(NPC),通过双溶剂浸渍法、化学还原法以及酸处理,制备了NPC负载铂铜的开放型合金纳米颗粒催化体系。通过形貌表征和氧还原催化活性测试,筛选出最佳催化剂,该催化剂也在电流-时间测试中,表现出卓越的稳定性。其催化性能的提升,主要基于铜的引入对金属铂的d带中心的调控以及NPC中氮掺杂位点、羰基官能团对于金属纳米颗粒的锚定作用。国家重点基础研究发展计划(973计划,2015CB932301

Synthesis, performance of Fe/N/C electrocatalysts for oxygen reduction and active sites study on model structure

燃料电池具有高效能、低排放等优势，是未来最有希望实现大规模商业化的清洁能源。目前，燃料电池主要采用Pt基贵金属作为催化剂，且其阴极氧还原反应(ORR)动力学迟缓，所需的Pt催化剂载量是阳极的10倍。然而贵金属Pt的储量稀少、价格昂贵，因此寻求开发储量丰富、价格低廉的非贵金属氧还原催化剂将大大降低燃料电池的成本。高温热解型Fe/N/C材料被认为是最有潜力的ORR非贵金属催化剂，受到了国内外研究学者的广泛关注。通常情况下，为了弥补与Pt基催化剂ORR活性的差距，Fe/N/C在燃料电池阴极的载量较高，而催化层厚度的增加（Fe/N/C为100μmvs.Pt/C为10μm）使阴极的传质变得更困难，因此改...With the advantages of high efficiency and low emissions, full cells are considered to be the most promising clean energy with large-scale commercialization in the future. Currently, Pt-base catalysts are necessary to drive both cathodic oxygen reduction reaction (ORR) and anodic hydrogen oxidation in full cells, and the slow kinetics for ORR result in Pt cathode loading that is 10 times as much a...学位：理学硕士院系专业：化学化工学院_物理化学学号：2052013115163

Effects of chemical treatment on the ORR activity of Fe/N/C electrocatalyst and study of active sites

燃料电池是一种具有发展前景的清洁转化装置，但受制于Pt等贵金属催化剂导致的高成本无法商业化。燃料电池阴极的非贵金属Me/N/C催化剂由于来源广，成本低，合成方法简单，成为目前的研究热点。但当前不同研究组使用不同的前驱体，只要优化合成条件都可以得到活性和稳定性相当的催化剂，这使得目前研究者对提高催化剂性能遇到了瓶颈。更多的研究者希望依据高活性的活性位的确定来理想设计制备具有高密度和高数量的活性位点的催化剂。活性位点的本质确定对合理设计催化剂来说是十分重要。但催化剂活性位点仍然处于争论状态，包括活性位中是否包含中心金属离子，金属离子对活性位的作用，及可能的催化活性位的组成，具有较高的研究价值。 ...The fuel cell as the most promising reformer has an extraordinary research value, but it can not be commercialized that be subject to precious metals. Due to the wide materials, low cost, simple synthesis methods, non-precious metal Me / N / C catalyst as the fuel cell cathode catalyst, become the hotspot. While even the use of different precursors, catalyst activity and stability may be of the sa...学位：理学硕士院系专业：化学化工学院_物理化学学号：2052013115165

Experimental Boosting of the Oxygen Reduction Activity of an Fe/N/C Catalyst by Sulfur Doping and Density Functional Theory Calculations

向Fe/N/C非贵金属催化剂中再引入S掺杂是进一步提高其氧还原催化活性的有效方法。为了探究活性提高的原因,本文以三聚氰胺-甲醛树脂为前驱体,氯化; 钙为模板,氯化铁为铁源,通过添加硫氰化钾(KSCN)来控制热解催化剂的S掺杂量。通过对比分析催化剂的物化性质,结合密度泛函理论(DFT)计算,分; 析S掺杂促进Fe/N/C催化剂氧还原活性的原因。透射电子显微镜(TEM)和N_2吸脱附等温线测试结果表明,S元素可抑制含铁纳米粒子的形成,促使形; 成多孔碳结构,提高比表面积。X射线光电子能谱(XPS)结果表明,适量S前驱体可实现较高的S掺杂含量,得到最优的活性,过量的S反而会导致Fe和S的; 掺杂量同时降低,影响活性。DFT计算结果表明在Fe-N_4大环中引入S掺杂,可增强O_2分子和中间体OOH与Fe-N_4结构中的Fe的相互作用,; 促进形成Fe―O键,从而导致O―O键的键能显著降低,为后续反应O―O键的断裂提供可能,促进ORR反应的进行。S doping in Fe/N/C non-precious metal catalysts is an effective approach to further improve their catalytic activity for the oxygen reduction reaction (ORR). However, the enhancement mechanism is not yet clear. Here, we synthesized an Fe/N/C catalyst using melamine-formaldehyde resin as the N and C precursors, CaCl2 as the template, and FeCl3 as the Fe precursor. The effects of S doping on the morphology, textural property, composition, and ORR catalytic activity were investigated by adding various amounts of KSCN as a precursor. Transmission electron microscopy (TEM) and N-2 adsorption-desorption isotherm results revealed that S prevented the growth of Fe-containing nanoparticles, and facilitated the formation of a porous structure, which increased both the catalyst surface area and mass transfer rate. X-ray photoelectron spectroscopy (XPS) results indicated that a suitable amount of S precursor led to a high doping level of S and provided the highest ORR activity. However, too much S in the precursor decreased the doping levels of both Fe and S, due to the formation of FeS, which could be completely removed by acid leaching. Density functional theory (DFT) calculations showed that the addition of S in an Fe-N-4 macrocycle could enhance the interaction strength of the Fe-O bond between the O-2 molecule or the intermediate OOHspecies and Fe in the Fe-N-4 structure, resulting in a significant decrease in the O-O bond energy, and may help in bond breaking in subsequent reactions, facilitating the ORR process.National Natural Science Foundation of China [21373175, 21621091

Iron Based Selenides: Structures, Compositions and Activities toward Oxygen Reduction Reaction

低温燃料电池包括碱性燃料电池和质子交换膜燃料电池，具有快速启动、比能量高和低温环境等特点，但需要贵金属铂作为催化剂。金属硒化物具有良好的电催化活性和化学稳定性，且成本低廉，是低温燃料电池阴极催化剂的候选材料。本论文采用简单的微波法，快速合成了一系列碳载铁基硒化物纳米催化剂，包括碳载铁硒化物（FeSe2/C）及碳载铁钴硒化物（FeCoSe/C）。通过表征催化剂的晶体结构、表面组成和形貌、微观结构及碳载体石墨化程度，系统探索了碳载体种类及添加顺序、铁源和溶剂种类、微波时间和硒/铁比值对催化剂氧还原活性及稳定性的影响，获得了具有较好氧还原活性和耐久性的铁基硒化物纳米催化剂。 结果表明，以草酸亚铁为...Low temperature fuel cells include alkaline fuel cell and proton exchange membrane fuel cell. They start up fast with high specific energy and can be operated at low temperatures. However, they have to use expensive precious platinum based metals as catalysts. Metal selenides exhibit good electrocatalytic activity toward oxygen reduction reaction (ORR) and chemical stability. They are low cost and...学位：工学硕士院系专业：材料学院_材料学学号：2072013115007

B, N Co-doped Carbon Materials Based on Polymer Precursor Design and Investigation of their Electrochemical Performances

碳基材料具有电导性、热稳定性、高比表面积、环境友好、来源广泛（资源丰富）等优点，在能源、催化等领域受到广泛关注。碳黑、富勒烯、碳纳米管、石墨烯等商业化碳材料的电中性和疏水表面限制了其作为催化剂或载体材料在能源领域的应用。杂原子的引入可以改变碳材料表面的润湿性和电荷分布，成为有利于电化学反应及金属纳米粒子分散的活性位点。本文借助于氧化聚合或缩合聚合形成自组装体的方法，构筑了含N、B元素的聚合物交联自组装体及TiO2@聚合物复合材料。经过高温热解制备了N或N、B共掺杂的碳材料以及可作为Pt纳米粒子载体的TiO2@CNB复合材料。通过模板法或含N、B元素的自组装基元调控，实现了掺杂碳材料及[email protected] materials have been widely investigated in energy-related field on account of their superior electrical conductivity, thermal stability, high specific surface area, environment friendly and broad source. The already commercialized carbon materials include carbon black, fullerene, carbon nanotube and graphene. However, their applications using as electrochemical catalysts or carrier ma...学位：工学博士院系专业：材料学院_材料物理与化学学号：2072012015330

Structure design of Fe/N/C electrocatalysts for oxygen reduction and its active sites study

热解型Fe/N/C作为最具潜力的非贵金属氧还原催化剂，其综合性能的进一步突破，对于推动低温燃料电池商业化应用具有极其重要的意义。不过，Fe/N/C催化剂仍面临着几方面的挑战。首先是传质扩散问题。Fe/N/C催化剂在燃料电池阴极的载量较高，其传质的难度远高于商业化的Pt/C(厚度100μmvs.10μm)。其次是对其活性位结构的认识。对活性位和反应机理的深入认识有助于进一步理性设计和提高Fe/N/C催化性能。然而，复杂、非均相结构、缺乏合适的表面表征技术和谱学技术，使得其活性位和催化机理研究止步不前。基于此，本文的工作主要分两部分展开：1)通过设计Fe/N/C催化剂的结构改善传质，包括制备复合碳...Pyrolyzed Fe/N/C is one of the most promising non-precious-metal catalysts for the oxygen reduction reaction (ORR), which is supposed to boost the commercialization of proton exchange membrane fuel cells (PEMFC). In spite of recent significant technological advances, a couple of major challenges remain on the way to the widespread application of Fe/N/C catalyst. The first challenge is mass transfe...学位：博士后院系专业：化学化工学院_物理化学学号：201417002