Wang Yunfei, Sun Du, Chowdhury Tomojit, Wagner Justine S, Kempa Thomas J, Hall Anthony Shoji
Department of Materials Science and Engineering , Johns Hopkins University , Baltimore , Maryland 21218 , United States.
Department of Chemistry , Johns Hopkins University , Baltimore , Maryland 21218 , United States.
J Am Chem Soc. 2019 Feb 13;141(6):2342-2347. doi: 10.1021/jacs.8b09919. Epub 2019 Feb 1.
Metal alloys with atomic scale ordering (ordered intermetallics) have emerged as a new class of high performance materials for mediating electrochemical reactions. However, ordered intermetallic nanostructures often require long synthesis times and/or high temperature annealing to form because a high-activation energy barrier for interdiffusion must be overcome for the constituent metals to equilibrate into ordered structures. Here we report the direct synthesis of metastable ordered intermetallic PdBi at room-temperature in minutes via electrochemical deposition. PdBi is highly active for the reduction of O to HO, delivering specific activities over 35× higher than those of commercial Pt and Pd nanocatalysts, placing it as the most active Pd-based catalyst, to the best of our knowledge, reported under similar testing conditions. Stability tests demonstrate minimal loss of activity after 10,000 cycles, and a retention of intermetallic crystallinity. This study demonstrates a new method of preparing ordered intermetallics with extraordinary catalytic activity at room temperature, providing a new direction in catalyst discovery and synthesis.
具有原子尺度有序性的金属合金（有序金属间化合物）已成为一类用于介导电化学反应的新型高性能材料。然而，有序金属间化合物纳米结构的形成通常需要较长的合成时间和/或高温退火，因为组成金属要达到平衡形成有序结构，必须克服互扩散的高活化能垒。在此，我们报告了通过电化学沉积在室温下几分钟内直接合成亚稳有序金属间化合物PdBi。PdBi对将O还原为H₂O具有高活性，其比活性比商业Pt和Pd纳米催化剂高出35倍以上，据我们所知，在类似测试条件下，它是活性最高的Pd基催化剂。稳定性测试表明，经过10000次循环后活性损失极小，且金属间化合物的结晶度得以保留。本研究展示了一种在室温下制备具有非凡催化活性的有序金属间化合物的新方法，为催化剂的发现和合成提供了新方向。
