摘要
Metal-semiconductor nanoheterostructure(NHS) exhibits fascinating catalytic performance due to the strong metal-support interaction(SMSI). SMSI in liquid-solid heterogeneous catalysis based on NHS was rarely investigated as compared to the gas-solid counterpart. Two issues, namely, the wet-chemical preparation of monodisperse model catalyst and in-situ characterization on the electronic structure, are challenging and studied here. The size of the metal catalyst was finely tuned in a Pd-Fe2O3 NHS and electrochemical test revealed that the electronic states differ significantly in liquid environment from in vacuum. The combined amendments resulted in a more reliable conclusion on the SMSI in Suzuki coupling. This study might give some clues on the illusive in-liquid structure-property relationships.
金属-氧化物型纳米异质结构可能存在界面间的电子和物质传输,因而导致性能的提升,目前得到广泛的关注.对于这类金属-氧化物型纳米异质结构在催化反应中的结构-效能关系,以往的研究存在以下不足之处:一方面对于尺寸的控制还有欠缺,不能合成尺寸可控的单分散样品;另一方面,对催化剂电子结构的表征主要停留在真空或气相环境,而液相原位表征方法亟待发展.本研究工作发展了一种甲酰胺溶剂合成体系,可以尺寸连续可调地合成一系列钯-氧化铁纳米异质结构和单独的钯纳米晶.利用这些模型催化剂,结合液相电化学测试方法,我们原位研究了它们的电子结构,并发现在真空和液相环境中,这些催化剂的电子结构有明显差异.这表明传统的真空表征方法可能会造成与真实构效关系的偏离.本研究表明,高质量的模型催化剂和原位表征方法对于研究构效关系都是至关重要的.这对于发展高效的金属-氧化物型液-固异相催化剂具有一定的启示意义.
基金
supported by the National Natural Science Foundation of China (NSFC) (91127040, 21221062)
the State Key Project of Fundamental Research for Nanoscience and Nanotechnology (2011CB932402)
