Observing metal-catalyzed chemical reactions in situ using surface-enhanced Raman spectroscopy on Pd-Au nanoshells.
Observing metal-catalyzed chemical reactions in situ using surface-enhanced Raman spectroscopy on Pd-Au nanoshells.
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DOI：
10.1021/ja803556k
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发表时间：
2008-12-10
影响因子：
15
通讯作者：
Wong MS
中科院分区：
文献类型：
--
作者：
Heck KN;Janesko BG;Scuseria GE;Halas NJ;Wong MS
深入了解瞬态反应中间体的性质和多相催化化学反应的机理途径可以从许多表面光谱技术中获得。在实际反应条件下进行这些研究是最好的，但仍然具有挑战性，特别是对于发生在水中的催化反应。在这里，我们报告了使用表面增强拉曼光谱（SERS）对水中1,1-二氯乙烯催化加氢脱氯的直接光谱研究。随着钯岛生长在金纳米壳膜上，利用SERS原位跟踪该反应，利用金纳米壳SERS基底的高增强和大活性面积，拉曼光谱对水溶液的透明度，以及底层金金属对钯的催化活性增强。观察了几种吸附质的形成和随后的转化。这些结果为氯化溶剂的室温催化加氢脱氯提供了第一个直接证据，作为脱氯和加氢步骤的序列，这是地下水净化的潜在重要途径。更广泛地说，这些结果强调了在水中原位研究催化过程的令人兴奋的前景，比如那些涉及生物质转化和质子交换膜燃料电池的过程。
Insight into the nature of transient reaction intermediates and mechanistic pathways involved in heterogeneously catalyzed chemical reactions is obtainable from a number of surface spectroscopic techniques. Carrying out these investigations under actual reaction conditions is preferred but remains challenging, especially for catalytic reactions that occur in water. Here, we report the direct spectroscopic study of the catalytic hydrodechlorination of 1,1-dichloroethene in H2O using surface-enhanced Raman spectroscopy (SERS). With Pd islands grown on Au nanoshell films, this reaction can be followed in situ using SERS, exploiting the high enhancements and large active area of Au nanoshell SERS substrates, the transparency of Raman spectroscopy to aqueous solvents, and the catalytic activity enhancement of Pd by the underlying Au metal. The formation and subsequent transformation of several adsorbate species was observed. These results provide the first direct evidence of the room-temperature catalytic hydrodechlorination of a chlorinated solvent, a potentially important pathway for groundwater cleanup, as a sequence of dechlorination and hydrogenation steps. More broadly, the results highlight the exciting prospects of studying catalytic processes in water in situ, like those involved in biomass conversion and proton-exchange membrane fuel cells.