Strong metal-support interaction (SMSI) is an important concept in heterogeneous catalysis. It is not only decisive in stabilizing active metals on supports, but also important in tuning catalytic performance and studying reaction mechanisms.
Au had been regarded as an inert metal for SMSI in the past few decades due to its relatively lower work function and surface energy. As a dynamic process taking place at the interface between Au nanoparticles(NPs) and the support, SMSI is closely related to the surface properties of Au NPs, which are profoundly influenced by the sizes of Au NPs.
Recently, Prof. QIAO Botao's group and Prof. LI Gao's group from the Dalian Institute of Chemical Physics (DICP) of the Chinese Academy of Sciences (CAS) discovered size effects on classical SMSI in Au/TiO2 catalysts, which provides a new approach to refine catalyst performance.
The results were published in Nature Communications on Nov. 16.
The researchers synthesized Au/TiO2 catalysts with different size distribution and investigated their SMSI performances.
They found that SMSI was more prone to occur on large Au NPs (~9 and ~13 nm) than on small ones (~3 and ~7 nm). A surface tension-dependent thermodynamic equilibrium model was established to explain the size effects.
Furthermore, the hydrogenation reaction selectivity of Au/TiO2 catalyst with an uneven particle size distribution was effectively improved by selectively encapsulating the large Au NPs as well as tuning the electronic property of the small ones.
This work may bring an in-depth understanding of SMSI mechanism, and provide an alternative approach to refine catalytic performance by tuning the SMSI state.
This study was supported by National Key Projects for Fundamental Research and Development of China, Strategic Priority Research Program of the Chinese Academy of Sciences, National Natural Science Foundation of China, DNL Cooperation Fund, LiaoNing Revitalization Talents Program, Innovation Fund of DICP, and Natural Science Foundation of China, and China Postdoctoral Science Foundation. (Text by DU Xiaorui)