DBFC燃料电池Au基合金催化剂结构设计、性能表征及电催化特性研究

The direct borohydride fuel cell (DBFC) has been extensively studied for many advantages, such as high fuel efficiency, easily to transport and conveniently to storage, no catalytic poisoning, and environmentally friendly. Moreover, DBFC has high theoretical open circuit voltage (1.64 V), high theoretical capacity (5.67 Ah/g) and energy convert efficiency (91%). The anode electrocatalyst is the key component in DBFC. In this proposal, we will focus on the design and synthesis of novel Au-based alloy catalysts. The chemical compositions, structures, physical and electrochemical properties of the synthesized electrocatalysts, and the electrocatalytic mechanisms for BH4- electrooxidation and hydrolysis reactions will be studied. The influence factors for the catalytic activity and stability of the catalysts, such as microstructure of catalysts and supports, bonding mechanism between catalysts and supports, experiment conditions during loading catalysts on supports. We will try to reveal the inter-correlation among these factors, and the relationship between these factors and the electrocatalytic performance of Au-based alloy catalysts. Furthermore, the mechanism for the decrease of catalytic activity and the increase of efficiency for the catalysts will be illuminated to develop new DBFC's anode electrocatalysts with low cost, good catalytic performance, and long-term durability. Half-cell and single-cell testing devices will be designed and the electrocatalytic mechanisms for the anode electrooxidation reaction will be studied by rotating disc electrode and fuel cell testing system, combined with current physical and chemical methods. The above studies would provide theoretical foundation and technological instruction for design and synthesis novel anode materials and develop new electrocatalysts for DBFC.

直接硼氢化钠燃料电池(DBFC)因其燃料效率高，燃料运输存储方便、无催化剂中毒，产物无污染且理论开路电压(1.64V)、理论比容量(5.67Ah/g)和能量转化率(91%)高而倍受关注。DBFC发展的关键是阳极电催化剂。设计并制备Au基合金系列催化剂，通过研究催化剂的组成、结构和性能的关系，探讨催化剂对BH4-阳极氧化反应和水解反应的电催化机理，研究催化剂和载体的微观结构与表面状态、催化活性组分与载体的键合机制及催化活性组分的负载工艺等对催化剂活性和稳定性的影响，揭示各因素相互之间及其与电催化活性之间的作用规律，阐明催化剂性能衰减和效能提高的机制，发展低成本、高性能、长寿命的阳极电催化剂。设计半电池和单体电池测试装置，利用旋转圆盘电极与燃料电池测试系统，结合现代物理化学和电化学研究手段进行系统研究，为优化和完善燃料电池电极材料制备技术、发展新型催化剂提供理论依据和实验方法指导。

直接硼氢化钠燃料电池(DBFC)主要以Pt、Au、Pd等贵金属作阳极催化剂，高的催化剂成本阻碍了DBFC的商业化。本项目针对限制DBFC商业化的瓶颈问题，从贵金属催化剂掺杂改性和新型催化剂碳载体的研发两方面着手，提高催化剂性能，降低其成本。主要研究了以下两部分内容：.1. 设计和制备了碳载Au-Fe双金属催化剂(Au-Fe/C)和新型纳米多孔碳(NPC)载Au催化剂(Au/NPC)等两种Au基纳米电催化剂，以及Pt-Sn/C，Pt-Zn/C，Pt-Cu/NPC，Pt/NPC和石墨烯载Pt(Pt/G)等Pt基纳米电催化剂。采用X-射线衍射(XRD)，透射电镜(TEM)，X-射线光电子能谱(XPS)，X-射线能谱(EDS)等研究了催化剂及碳载体的组成，结构，形貌；采用线性扫描伏安(LSV)，循环伏安(CV)，计时电流(CA)，计时电位(CP)等研究了催化剂对BH4-电催化氧化反应的催化特性；用旋转圆盘电极(RDE)测定了BH4-在催化剂电极上电催化氧化反应的反应电子数。设计和制备了DBFC单池测试装置，对以上催化剂材料作阳极催化剂的DBFC进行了电池性能测试。研究了催化剂和载体的微观结构，表面形态，催化剂活性组分，载体的比表面积，孔径分布等对催化剂催化活性与稳定性的影响。研究结果表明，3d过渡态金属掺杂能明显提高贵金属催化剂的催化活性，XPS结果表明其原因是双金属之间的电子效应；采用新型碳材料NPC和石墨烯作催化剂载体，催化剂的催化活性和稳定性均得到了提高。催化活性高的阳极催化剂所对应的DBFC的电池性能也更好。.2. 研究了系列新型碳材料，拟将其应用于纳米电催化剂的载体进行研究。设计和制备了三维立方有序介孔碳(OMCs)，层次多孔炭微球(HPCMS)，三维有序层次多孔碳(3D HOPC)，N掺杂三维层次多孔碳(N-3DHPC)，碳微球(CMB)，富氮碳微球(NENC)和多孔碳化钙骨架碳(CCDC)等具有特殊形貌的新型碳材料，并对其进行了表面修饰和性能改进。所制备的碳材料的组成，结构，形貌，表面元素组成，表面官能团，比表面积和孔径分布等物理性质分别采用XRD，SEM，TEM，XPS，氮气吸/脱附等进行了系统的表征。