Department of Materials Science and Engineering, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, USA.
J Am Chem Soc. 2013 May 29;135(21):7985-91. doi: 10.1021/ja402072r. Epub 2013 May 16.
The ability to direct bimetallic nanoparticles to express desirable surface composition is a crucial step toward effective heterogeneous catalysis, sensing, and bionanotechnology applications. Here we report surface composition tuning of bimetallic Au-Pt electrocatalysts for carbon monoxide and methanol oxidation reactions. We establish a direct correlation between the surface composition of Au-Pt nanoparticles and their catalytic activities. We find that the intrinsic activities of Au-Pt nanoparticles with the same bulk composition of Au0.5Pt0.5 can be enhanced by orders of magnitude by simply controlling the surface composition. We attribute this enhancement to the weakened CO binding on Pt in discrete Pt or Pt-rich clusters surrounded by surface Au atoms. Our finding demonstrates the importance of surface composition control at the nanoscale in harnessing the true electrocatalytic potential of bimetallic nanoparticles and opens up strategies for the development of highly active bimetallic nanoparticles for electrochemical energy conversion.
将双金属纳米粒子定向表达所需的表面组成是实现高效多相催化、传感和生物纳米技术应用的关键步骤。在这里，我们报告了用于一氧化碳和甲醇氧化反应的双金属 Au-Pt 电催化剂的表面组成调谐。我们确定了 Au-Pt 纳米粒子的表面组成与其催化活性之间的直接相关性。我们发现，具有相同 Au0.5Pt0.5 体组成的 Au-Pt 纳米粒子的本征活性可以通过简单地控制表面组成来提高几个数量级。我们将这种增强归因于在离散的 Pt 或 Pt 富簇周围的表面 Au 原子上，CO 在 Pt 上的结合被削弱。我们的发现证明了在纳米尺度上控制表面组成对于利用双金属纳米粒子的真正电催化潜力的重要性，并为开发用于电化学能量转换的高活性双金属纳米粒子开辟了新的策略。
