Photochemistry of Plasmonic Titanium Nitride Nanocrystals
Photochemistry of Plasmonic Titanium Nitride Nanocrystals
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DOI：
10.1021/acs.jpcc.9b06257
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发表时间：
2019-09-05
影响因子：
3.7
通讯作者：
Mangolini, Lorenzo
中科院分区：
文献类型：
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作者：
Barragan, Alejandro Alvarez;Hanukovich, Sergei;Mangolini, Lorenzo
氮化钛（TiN）在热稳定性、成本和可持续性方面提供了与诸如金和银的标准使用的等离子体材料相比的优点。虽然金和银纳米结构在等离子体激元催化的快速发展领域中发挥了重要作用，但TiN在该应用中的潜力仍有待开发。在这里，我们提供的证据等离子体驱动的化学活性在TiN通过使用铂离子的光还原在可见光-近红外（vis-NIR）照明作为探针反应。将TiN、甲醇和氯铂酸（H2 PtCl 6）的水溶液暴露于可见-NIR辐射（600-900 nm）。扫描透射电子显微镜（STEM）、能量色散X射线光谱（EDX）和X射线光电子能谱（XPS）显示由类似于2 nm金属铂簇组成的纳米结构，其装饰类似于10 nm TiN纳米颗粒，证实了等离子体驱动的Pt 4+离子还原为其金属状态。同时，通过气相色谱法监测甲醇光氧化产生的CO2的释放。Pt沉积与CO2析出的摩尔比与基于氧化还原反应电荷平衡的理论预期吻合得很好。我们已经发现，Pt沉积和CO2的演变是自限制的。我们将此归因于在光还原过程中等离子体激元退相速率的增加，这可能是由于Pt在可见-近红外区域中的高光学损耗。此外，Pt（111）-TiN（111）结的密度泛函理论（DFT）模拟表明存在限制电子转移的能垒。这项工作证实了等离子体TiN纳米颗粒可以利用可见光来驱动光化学反应，并强调了TiN作为金和银的经济有效替代品的潜力。
Titanium nitride (TiN) offers advantages compared to standardly used plasmonic materials such as gold and silver in terms of thermal stability, cost, and sustainability. While gold and silver nanostructures have played an important role in the rapidly growing field of plasmonic catalysis, the potential of TiN in this application is still underexplored. Here we provide evidence of plasmon-driven chemical activity in TiN by using the photoreduction of platinum ions under visible-near-infrared (vis-NIR) illumination as probe reaction. An aqueous solution of TiN, methanol, and chloroplatinic acid (H2PtCl6) was exposed to vis-NIR radiation (600-900 nm). Scanning transmission electron microscopy (STEM), energy-dispersive X-ray spectroscopy (EDX), and X-ray photoelectron spectroscopy (XPS) show nanostructures composed of similar to 2 nm metallic platinum clusters decorating similar to 10 nm TiN nanoparticles, confirming the plasmon-driven reduction of the Pt4+ ions to their metallic state. At the same time, the evolution of CO2 resulting from the photooxidation of methanol is monitored via gas chromatography. The molar Pt deposition-to-CO2 evolution ratio is in good agreement with the theoretical expectation based on the redox reaction charge balance. We have found that both Pt deposition and CO2 evolution are self-limiting. We attribute this to the increasing plasmon dephasing rate during the photoreduction process, likely due to the high optical losses of Pt in the vis-NIR region. In addition, density functional theory (DFT) simulations of a Pt(111)-TiN(111) junction suggest the existence of an energy barrier limiting electron transfer. This work confirms that plasmonic TiN nanoparticles can use visible light to drive photochemical reactions and highlights the potential of TiN as a cost-effective alternative to gold and silver.