The Electrochemical Energy, Catalysis, and Materials Science Laboratory, Department of Chemistry, Chemical Engineering Division, Technical University Berlin, 10623 Berlin, Germany.
Nat Chem. 2010 Jun;2(6):454-60. doi: 10.1038/nchem.623. Epub 2010 Apr 25.
Electrocatalysis will play a key role in future energy conversion and storage technologies, such as water electrolysers, fuel cells and metal-air batteries. Molecular interactions between chemical reactants and the catalytic surface control the activity and efficiency, and hence need to be optimized; however, generalized experimental strategies to do so are scarce. Here we show how lattice strain can be used experimentally to tune the catalytic activity of dealloyed bimetallic nanoparticles for the oxygen-reduction reaction, a key barrier to the application of fuel cells and metal-air batteries. We demonstrate the core-shell structure of the catalyst and clarify the mechanistic origin of its activity. The platinum-rich shell exhibits compressive strain, which results in a shift of the electronic band structure of platinum and weakening chemisorption of oxygenated species. We combine synthesis, measurements and an understanding of strain from theory to generate a reactivity-strain relationship that provides guidelines for tuning electrocatalytic activity.
电催化在未来的能源转换和存储技术中发挥着关键作用，例如水电解槽、燃料电池和金属空气电池。化学反应物与催化表面之间的分子相互作用控制着活性和效率，因此需要进行优化；然而，通用的实验策略却很少。在这里，我们展示了如何通过实验利用晶格应变来调节脱合金双金属纳米颗粒对氧还原反应的催化活性，这是燃料电池和金属空气电池应用的关键障碍。我们证明了催化剂的核壳结构，并阐明了其活性的机械起源。富铂壳层表现出压缩应变，导致铂的电子能带结构发生位移，含氧物种的化学吸附减弱。我们结合合成、测量和理论上对应变的理解，生成了一个反应性-应变关系，为调节电催化活性提供了指导。
