重整催化层对金属支撑SOFC抗积碳性能的影响机理研究

Metal-supported solid oxide fuel cell (MS-SOFC), which offers many advantages compared to the conventional electrode- and electrolyte-supported SOFC, such as excellent structural robustness and stability, high tolerance toward rapid thermal cycling, easy stack assembling and low material cost, has gained increasing attention. However, the research on state-of-the-art of MS-SOFC are mainly focusing on the hydrogen fuel, minor attention has been paid to the hydrocarbon fuel. The principal problems to be solved when use methane as fuel in MS-SOFC is the carbon deposition of nickel-based anode, which is the same as in traditional SOFC. To solve this issue, a multi-layer anode that composed of reforming layer is applied in traditional SOFC, and the key point is to develop high active and stable catalyst. Motivated by this method, an internal reforming layer is adopted in this proposal in order to achieve the long-term stability of MS-SOFC operating in methane fuel. By investigating the interaction between catalyst and catalytic agent, and their effect on the carbon resistance and electrochemical properties of multi-layer anode, the optimum catalyst composition can be obtained. Subsequently, the reforming layer will be screen-printing and in-situ sintering and reducing on the anode substrate to form a multi-layer anode. Three-dimensional reconstruction technique will be used to guide the controllable preparation. Effect of reforming layer on the carbon deposition behavior and electrochemical performance of multi-layer anode will be evaluated and, the influencing mechanism will be discussed. This proposal will provide theoretical fundamental for development of carbon resistance anode with high catalytic activity and stability in direct methane MS-SOFC.

与传统电极支撑和电解质支撑固体氧化物燃料电池相比，金属支撑固体氧化物燃料电池（MS-SOFC）具有良好的结构稳定性、快速热循环耐受性、以及易于装堆且成本较低等优点，受到广泛的关注。但是目前关于MS-SOFC的研究主要是以氢气为燃料，几乎没有采用碳氢燃料的报道。在MS-SOFC中使用甲烷为燃料同样存在Ni基阳极的积碳问题。在传统SOFC中，通过构建含有重整层的多层阳极是抗积碳的一种有效方法，而开发高效稳定的重整催化剂是其中的关键。本研究借鉴上述方法构建含有重整催化层的MS-SOFC，通过研究催化剂及其助剂之间的相互作用以及对催化剂性能及稳定性的影响，优选催化剂组成。采用丝网印刷-原位烧结还原方法构建多层阳极结构，利用三维重构技术指导多层阳极的可控制备，并考察重整层对多层阳极抗积碳性能和电化学性能的影响，揭示其抗积碳作用机理，为开发MS-SOFC高效抗积碳阳极提供科学依据。

在金属支撑固体氧化物燃料电池（MS-SOFC）中使用甲烷为燃料同样存在Ni基阳极的积碳问题。在传统SOFC中，通过构建含有重整层的多层阳极是抗积碳的一种有效方法，而开发高效稳定的重整催化剂是其中的关键。本研究借鉴上述方法构建含有重整催化层的MS-SOFC，研究了催化剂及其助剂之间的相互作用以及对催化剂性能及稳定性的影响，优选了催化剂组成。采用丝网印刷-原位烧结还原方法构建多层阳极结构，利用三维重构技术指导了多层阳极的可控制备，并考察了重整层对多层阳极抗积碳性能和电化学性能的影响，揭示了其抗积碳作用机理，主要的研究结果如下：.1）开发并优选了Ni0.5Cu0.5Mg0.05Fe2O4-BaZr0.1Ce0.7Y0.1Yb0.1O3-δ（N-B）催化重整层催化材料。优选后的N-B82/Ni-YSZ表现出比Ni-YSZ更好的催化性能，以N-B82为催化重整层，采用流延-丝网印刷-高温烧结制备了Ni-Fe合金支撑的SOFC单电池，具有更高的CH4转化率和CO选择性，以及更好的长期稳定性。.2）BZCYYb对水具有较好的吸附性，使得其具有良好的抗积碳性能；BZCYYb在单一CO2中的毒化临界温度为400-500℃之间，水的引入会加速BZCYYb的毒化分解，进而影响其长期稳定性。.3）开发并优选了La0.8-xSrxCr0.85Ni0.15O3-δ催化重整层催化材料，通过原位析出法在其表面析出了金属Ni纳米颗粒，还原后的La0.6Sr0.2Cr0.85Ni0.15O3获得了最佳的催化效率，在750°C经过24小时测试后CH4和CO2的转化率仍保持在90%以上。以LSCN-GDC作为催化重整层的SOFC单电池，在50%CO2-50%CH4燃料中表现出良好的放电性能和长期稳定性，同时在400 mA cm-2和750°C下进行36小时的长期放电测试不积碳。绝大部分CH4与CO2能被重整层转化生成H2和CO，减少了CH4与阳极的直接接触，使得SOFC能够高效地利用CH4进行稳定的发电。.4）采用NiMn2O4尖晶石对传统Ni-GDC阳极进行修饰，制备了多孔Ni-Fe合金支撑的SOFC单电池，NiMn2O4在阳极分解为Ni和MnO，由于支撑体中的Fe和阳极中的Mn在电池制备过程中扩散进入GDC提高了其电导率，并且MnO抑制了Ni的烧结团聚，提高了单电池的放电性能和抗积碳性能。