Ano Taishi, Kishimoto Fuminao, Sasaki Ryo, Tsubaki Shuntaro, Maitani Masato M, Suzuki Eiichi, Wada Yuji
Department of Applied Chemistry, Tokyo Institute of Technology, 2-12 Ookayama, Meguro, Tokyo 152-8552, Japan.
Phys Chem Chem Phys. 2016 May 11;18(19):13173-9. doi: 10.1039/c6cp02034h.
We demonstrate two novel methods for the measurement of the temperatures of reaction spaces locally heated by microwaves, which have been applied here to two example systems, i.e., BaTiO3 particles covered with a SiO2 shell (BaTiO3-SiO2) and layered tungstate particles. Photoluminescent (PL) probes showing the temperature-sensitivity in their PL lifetimes are located in the nanospaces of the above systems. In the case of BaTiO3-SiO2 core-shell particles, rhodamine B is loaded into the mesopores of the SiO2 shell covering the BaTiO3 core, which generates the heat through the dielectric loss of microwaves. The inner nanospace temperature of the SiO2 shell is determined to be 28 °C higher than the bulk temperature under microwave irradiation at 24 W. On the other hand, Eu(3+) is immobilized in the interlayer space of layered tungstate as the PL probe, showing that the nanospace temperature of the interlayer is only 4 °C higher than the bulk temperature. This method for temperature-measurement is powerful for controlling microwave heating and elucidates the ambiguous mechanisms of microwave special effects often observed in chemical reactions, contributing greatly to the practical application of microwaves in chemistry and materials sciences.
我们展示了两种用于测量由微波局部加热的反应空间温度的新方法，这里已将其应用于两个示例系统，即覆盖有SiO₂壳的BaTiO₃颗粒（BaTiO₃-SiO₂）和层状钨酸盐颗粒。在上述系统的纳米空间中放置了在其光致发光（PL）寿命中表现出温度敏感性的光致发光（PL）探针。对于BaTiO₃-SiO₂核壳颗粒，罗丹明B被加载到覆盖BaTiO₃核的SiO₂壳的介孔中，其通过微波的介电损耗产生热量。在24 W微波辐射下，SiO₂壳的内部纳米空间温度被确定比本体温度高28℃。另一方面，Eu(3+)作为PL探针固定在层状钨酸盐的层间空间中，表明层间的纳米空间温度仅比本体温度高4℃。这种温度测量方法对于控制微波加热很有效，并阐明了在化学反应中经常观察到的微波特殊效应的模糊机制，对微波在化学和材料科学中的实际应用有很大贡献。
