In situ dynamic tracking of heterogeneous nanocatalytic processes by shell-isolated nanoparticle-enhanced Raman spectroscopy.
In situ dynamic tracking of heterogeneous nanocatalytic processes by shell-isolated nanoparticle-enhanced Raman spectroscopy.
复制标题
通过壳隔离纳米颗粒增强拉曼光谱对异质纳米催化过程进行原位动态跟踪
DOI：
10.1038/ncomms15447
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发表时间：
2017-05-24
影响因子：
16.6
通讯作者：
Tian ZQ
中科院分区：
文献类型：
--
作者：
Zhang H;Wang C;Sun HL;Fu G;Chen S;Zhang YJ;Chen BH;Anema JR;Yang ZL;Li JF;Tian ZQ
从催化过程中原位获取的表面分子信息可以通过揭示结构-活性关系和反应机制，极大地促进高效催化剂的合理设计。拉曼光谱可以提供丰富的结构信息，但普通拉曼光谱的灵敏度不足以检测催化剂表面吸附的痕量活性物质。在这里，我们开发了一种通过壳隔离纳米颗粒增强拉曼光谱（SHINERS）卫星纳米复合材料（金核二氧化硅壳纳米催化剂卫星结构）原位监测异相催化过程的通用方法，该复合材料稳定且具有极高的表面拉曼灵敏度。通过将操作 SHINERS 与密度泛函理论计算相结合，我们确定了 PtFe 和 Pd 纳米催化剂（分别是典型的低温和高温催化剂）上 CO 氧化的工作机制。在反应过程中可以直接观察到活性物质，例如表面氧化物、超氧化物/过氧化物物质和 Pd-C/Pt-C 键。我们证明原位 SHINERS 可以加深对催化基本概念的理解。多相催化剂的合理设计需要对催化过程的分子理解。在这里，作者将 PtFe 和 Pd 纳米催化剂附着在拉曼信号增强的金二氧化硅纳米粒子上，使他们能够实时光谱观察参与 CO 氧化的活性物质和键。
Surface molecular information acquired in situ from a catalytic process can greatly promote the rational design of highly efficient catalysts by revealing structure-activity relationships and reaction mechanisms. Raman spectroscopy can provide this rich structural information, but normal Raman is not sensitive enough to detect trace active species adsorbed on the surface of catalysts. Here we develop a general method for in situ monitoring of heterogeneous catalytic processes through shell-isolated nanoparticle-enhanced Raman spectroscopy (SHINERS) satellite nanocomposites (Au-core silica-shell nanocatalyst-satellite structures), which are stable and have extremely high surface Raman sensitivity. By combining operando SHINERS with density functional theory calculations, we identify the working mechanisms for CO oxidation over PtFe and Pd nanocatalysts, which are typical low- and high-temperature catalysts, respectively. Active species, such as surface oxides, superoxide/peroxide species and Pd–C/Pt–C bonds are directly observed during the reactions. We demonstrate that in situ SHINERS can provide a deep understanding of the fundamental concepts of catalysis. Rational design of heterogeneous catalysts requires molecular understanding of catalytic processes. Here, the authors attach PtFe and Pd nanocatalysts to Raman signal-enhancing Au-silica nanoparticles, allowing them to spectroscopically observe the active species and bonds involved in CO oxidation in real time.