原位表面修饰与镍/钴/氮高效可控共掺杂增强碳空心球电催化活性的研究

Highly efficient controllable metal/nitrogen co-doping and surface functionalized modification of carbon hollow sphere can greatly improve its electrochemical behaviors, which possesses significant applications in the field of energy electrochemistry. This project will firstly investigate the impregnation process of the carbon hollow sphere (CHS) particles in the solutions containing various nitrogen sources (e.g., melamine, aniline and pyrrole) in the absence or presence of nickel/cobalt salts. The nitrogen sources will be infiltrated into the interior of the CHS particles at normal atmospheric pressure or under pressure. Then a film of nitrogen-doped graphene or C-N hollow nanotubes is in situ formed on the surface of the CHS particles through a high-temperature pyrolysis, resulting in the formation of metal/nitrogen co-doped CHS modified by C-N nano-composites (Ni/Co/N-CHS@C-N). This C-N nano-composite film can greatly enhance the electrochemical behaviors of the Ni/Co/N doped CHS surface, as well as the stability of the doped metal. Step temperature-controlled pyrolysis and controlling the size and wall thickness of CHS will be applied in order to achieve the highly efficient controllable co-doping nickel/cobalt/nitrogen. This project will systematically study the effect of the various nitrogen sources, different nitrogen doping methods, extent and mechanism of the C-N nano-composites modification of the CHS surfaces on the electrochemical properties of the Ni/Co/N-CHS@C-N materials, such as electrochemical capacitance, electroactivity for oxygen reduction reaction and alcohol oxidation, and the electrochemical properties as a substrate of electrocatalysts, and also study the dependence of the nitrogen content and binding pattern on the Ni/Co/N-CHS@C-N materials upon the electrochemical properties. It will be of great significance on science for the research of this project on the prepartion of the doped carbon hollow spheres with excellent electrochemical properties.

对碳空心球(CHS）进行高效可控的金属/氮共掺杂，并对其表面进行功能化修饰，能显著改善它的电化学性质，在能源电化学领域有重要应用。本项目首先通过加压浸渍过程，将镍钴盐和氮源渗透进入CHS内部；随后采用高温热解技术，在CHS表面原位形成氮掺杂石墨烯或C-N空心纳米管，得到表面C-N复合物修饰的金属/氮共掺杂碳空心球催化剂Ni/Co/N-CHS@C-N，从而显著增强CHS的电化学催化活性，并有效提高掺杂金属的稳定性。采用分步控温热解并通过控制CHS的大小与壁厚，实现镍/钴/氮的高效可控共掺杂。通过研究Ni/Co/N-CHS@C-N催化剂的电化学电容特性、对醇氧化与氧还原的电催化活性以及作为催化剂载体的性能等，探索不同的氮源与掺氮方式、不同C-N复合物修饰的程度与机理、催化剂中氮的含量和存在形态等因素对它们的电化学性能的影响，为制备电化学性能优异的掺杂CHS提供科学依据。

对碳空心球(HCS)进行高效可控的金属/杂原子共掺杂，并对其表面进行功能化修饰，能显著.改善它的电化学性质，在能源电化学领域有重要应用。本项目研究了HCS的N/P/B元素的共掺杂以及石墨烯修饰等对HCS电化学性质的影响，研究了负载Fe/Co/Ni/Pt纳米颗粒的氮掺杂HCS的制备以及电化学性质，研究了不同微观结构的碳与NHCS形成的复合物的制备及其电化学活性，主要研究内容有：（1）利用氧化石墨烯(GO)与氮掺杂空心碳球(NHCS)之间的静电吸引，制备了GO修饰的NHCS，在碱性/中性介质中均表现出可媲美于商品Pt/C的氧还原反应（ORR）活性，它们是碱性/中性锌空气电池优异的阴极催化剂；（2）利用简单热解过程，制备了N/P/B共掺杂的HCS复合物，它们在碱性和中性溶液中表现出比Pt/C更正的ORR起始电位和半波电位，作为空气电极催化剂，在锌-空气电池中表现出高度的稳定性；（3）在NHCS球表面原位制备管状碳，通过改变NHCS球状颗粒与管状碳颗粒的比例，对所得到的复合物CoNi/NHCS-TUC-x进行结构调控，使它们具有优异的ORR/OER双功能电活性，应用于锌-空气电池时具有高度稳定的充放电活性；（4）通过将NHCS与MOF材料结合，在进一步高温热解后得到球形碳和多面体碳氮结合所形成的复合物(Fe-NC@NHCS)，这种复合物结合了球形碳和多面体碳在改善ORR和OER电活性上的优势，在全域pH范围内（酸性、碱性、中性）均表现出优异的ORR活性，并且是可充式锌-空气电池优异的双功能阴极催化剂；（5）利用多巴胺与金属离子间的配位作用，将金属原位嵌入HCS的碳层内，高温热解后形成负载Fe/Co纳米颗粒的NHCS复合物，它们在碱性和中性溶液中表现出优异的ORR电活性，也是相应的锌-空气电池高效而稳定的阴极催化剂；（6）利用热还原法，在CoNi/NHCS-TUC-x和Fe-NC@NHCS表面沉积少量铂得到低载量铂催化剂，应用于PEMFC时获得良好的效果;（7）以NHCS为基体，通过结合MnO2,、聚苯胺和Ni2CoS4等纳米颗粒，形成的复合物具有优异的电化学电容特性；（8）杂原子掺杂与Fe/Co/Ni纳米颗粒的加入，以及对微观结构的调控，使HCS具有丰富的活性位点和巨大的活性表面积，导致其具有优异的电化学活性和高度的稳定性。