Measuring oxygen reduction/evolution reactions on the nanoscale
Measuring oxygen reduction/evolution reactions on the nanoscale
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DOI：
10.1038/nchem.1112
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发表时间：
2011-09-01
期刊：
影响因子：
21.8
通讯作者：
Jesse, Stephen
中科院分区：
文献类型：
--
作者：
Kumar, Amit;Ciucci, Francesco;Jesse, Stephen
燃料电池和金属-空气电池的效率受到氧还原和析出反应的活化的显著限制。尽管氧反应动力学对能源技术的可行性具有公认的作用，但其控制机制仍然难以捉摸，迄今为止只能通过宏观研究来解决。这种对纳米尺度理解的缺乏阻碍了材料结构的优化。在这里，我们报告的直接测量的氧还原/演化反应和氧空位扩散的氧离子导电固体表面与子10 nm的分辨率。在电化学应变显微镜中，偏置扫描探针显微镜针尖充当移动的电催化活性探针，探索局部电化学活性。该探头集中在一个纳米级的材料体积的电场，和偏置诱导，皮米级的表面位移提供信息的局部电化学过程。系统映射的氧活性裸和铂功能化的氧化钇稳定的氧化锆表面上证明。这种方法允许在三相边界处的氧还原/析出反应活化过程的直接可视化，并且可以扩展到宽范围的氧传导和电催化材料。
The efficiency of fuel cells and metal-air batteries is significantly limited by the activation of oxygen reduction and evolution reactions. Despite the well-recognized role of oxygen reaction kinetics on the viability of energy technologies, the governing mechanisms remain elusive and until now have been addressable only by macroscopic studies. This lack of nanoscale understanding precludes optimization of material architecture. Here, we report direct measurements of oxygen reduction/evolution reactions and oxygen vacancy diffusion on oxygen-ion conductive solid surfaces with sub-10 nm resolution. In electrochemical strain microscopy, the biased scanning probe microscopy tip acts as a moving, electrocatalytically active probe exploring local electrochemical activity. The probe concentrates an electric field in a nanometre-scale volume of material, and bias-induced, picometre-level surface displacements provide information on local electrochemical processes. Systematic mapping of oxygen activity on bare and platinum-functionalized yttria-stabilized zirconia surfaces is demonstrated. This approach allows direct visualization of the oxygen reduction/evolution reaction activation process at the triple-phase boundary, and can be extended to a broad spectrum of oxygen-conductive and electrocatalytic materials.