Hemoglobin pyropolymer used as a precursor of a noble-metal-free fuel cell cathode catalyst
Hemoglobin pyropolymer used as a precursor of a noble-metal-free fuel cell cathode catalyst
复制标题
DOI：
10.1021/jp709912d
复制
发表时间：
2008-02-21
影响因子：
3.7
通讯作者：
Abe, Ikuo
中科院分区：
文献类型：
--
作者：
Maruyama, Jun;Okamura, Junji;Abe, Ikuo
血红蛋白的部分热解产生血红蛋白热聚合物，它是聚合物和碳质材料之间的中间物质。该热聚合物是由血红蛋白在600℃以下热处理形成的。通过热重分析和差热分析研究了热聚合物的形成行为，并通过元素分析和C-13核磁共振谱对热聚合物进行了表征。热聚合物的形成在 200 摄氏度左右开始，随着热处理温度的升高，通过血红蛋白中脂肪族碳的转化而形成芳香族碳。通过在含有 10% CO2 的流动 Ar 中对血红蛋白热聚合物进行热处理，形成用于聚合物电解质燃料电池（PEFC）的不含贵金属的阴极催化剂。催化剂的活性取决于热聚合物的特性。碳基质随着芳香碳的增加而发展，而微孔的发展受到抑制。观察到具有最大微孔发展的催化剂的最高活性。使用本研究中获得的最高活性催化剂的PEFC在O-2分压54和254 kPa下分别产生0.12和0.23 W cm(-2)。连续PEFC操作和扩展X射线吸收精细结构的测量表明，操作期间电流的减少与催化剂活性位点的结构相关。
The partial pyrolysis of hemoglobin yielded the hemoglobin pyropolymer, which is an intermediate substance between a polymer and carbonaceous material. The pyropolymer was formed by the heat treatment of hemoglobin below 600 degrees C. The formation behavior of the pyropolymer was examined by thermogravimetry and differential thermal analysis, and the pyropolymer was characterized by elemental analysis and its C-13 nuclear magnetic resonance spectrum. The pyropolymer formation began around 200 degrees C, and aromatic carbon developed with an increase in the heat-treatment temperature through transformation of the aliphatic carbon in hemoglobin. A noble-metal-free cathode catalyst for a polymer electrolyte fuel cell (PEFC) was formed by heat treatment of the hemoglobin pyropolymer in flowing Ar containing 10% CO2. The activity of the catalyst was dependent on the characteristics of the pyropolymer. The carbon matrix developed with an increase in the aromatic carbon, whereas the micropore development was suppressed. The highest activity was observed for the catalyst with the maximized micropore development. The PEFC using the catalyst with the highest activity obtained in this study generated 0.12 and 0.23 W cm(-2) at O-2 partial pressures of 54 and 254 kPa, respectively. Continuous PEFC operations and measurements of the extended X-ray absorption fine structures demonstrated that the current decrease during the operation correlated with the structure of the active site of the catalyst.