X-ray evaluation of the boundary between polymer electrolyte and platinum and carbon functionalization to conduct protons in polymer electrolyte fuel cells
X-ray evaluation of the boundary between polymer electrolyte and platinum and carbon functionalization to conduct protons in polymer electrolyte fuel cells
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X射线评估聚合物电解质与铂和碳功能化之间的边界以在聚合物电解质燃料电池中传导质子
DOI：
10.1016/j.jpowsour.2014.02.040
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发表时间：
2014
期刊：
影响因子：
--
通讯作者：
泉康雄
中科院分区：
文献类型：
--
作者：
岡和輝;小倉優太;泉康雄
在聚合物电解质燃料电池（PEFC）中，确保反应物和电子的邻近扩散路径非常重要。一种方法是优化聚合物电解质和 Pt 纳米粒子表面之间的边界。基于同步加速器X射线吸收精细结构直接监测PEFC中催化剂的状态，发现在PEFC阴极制备过程中，聚合物电解质分散液中所含的醇将Pt位点还原为Pt0。与膜电解质组件一样，只有未被聚合物电解质覆盖的 Pt 位点被重新氧化为 Pt2+/4+。由此，评价Pt和聚合物电解质之间的界面。另一种方法是用磺酸盐/硫酸盐基团对碳表面进行功能化以传导质子。与使用聚合物电解质相比，在电流-电压依赖性方面观察到类似水平的质子电导率，但聚合物电解质有利于损失更少的激活电压。基于此比较，提出了阴极上的最佳催化剂，其包含与聚合物电解质混合的碳上的表面磺酸盐/硫酸盐基团。提出进一步优化阴极催化剂，用连接到氟碳支链的磺酸基团对碳进行官能化。
In polymer electrolyte fuel cells (PEFCs), it is important to secure proximate diffusion paths of reactants and electrons. One approach is to optimize the boundary between polymer electrolyte and Pt nanoparticle surface. Based on synchrotron X-ray absorption fine structure to monitor directly the status of catalysts in PEFCs, it was found that Pt sites were reduced to Pt0by alcohols contained in polymer electrolyte dispersion solution during the preparation of cathode of PEFC. As in membrane electrolyte assembly, only the Pt sites not covered by polymer electrolyte re-oxidized to Pt2+/4+. Thus, the interface between Pt and polymer electrolyte was evaluated. The other approach is to functionalize carbon surface with sulfonate/sulfate group to conduct protons. Similar level of proton conductivity was observed in current–voltage dependence compared to using polymer electrolyte, but polymer electrolyte was advantageous to lose less voltage for activation. Based on this comparison, optimum catalyst on cathode is proposed comprising surface sulfonate/sulfate group on carbon mixed with polymer electrolyte. Further optimization of cathode catalyst is proposed to functionalize carbon with sulfonate group linked to fluorocarbon branch.