Recently, the research group led by Prof. Qiang Fu and Prof. Xinhe Bao from Dalian Institute of Chemical Physics, Chinese Academy of Sciences, demonstrated the strong metal-support interaction (SMSI) effect in molybdenum carbide-supported Au catalyst (Au/MoCx). This work has been published as an article in Journal of the American Chemical Society (J. Am. Chem. Soc. 2018, 140, 42, 13808-13816), with the title of “Carbide-Supported Au Catalysts for Water–Gas Shift Reactions: A New Territory for the Strong Metal–Support Interaction Effect”.
Strong metal−support interaction (SMSI) has been regarded as one of the most important concepts in heterogeneous catalysis. The classical SMSI phenomena are widely observed for platinum group metals (PGMs) supported on reducible oxides such as TiO2, CeO2, and Fe2O3 upon high-temperature reduction treatments. Transition-metal carbides (TMCx) exhibit noble-metal-like electronic properties, which are promising as catalytic materials or catalyst supports in many reactions. Recently, there is a call for studies of the SMSI effect in metal/carbide systems in order to extend the important concept and to elucidate the nature of metal−carbide interactions.
In this work, both Au catalyst and MoCx support have been chosen to construct the metal/carbide interfaces. They found that Au remains highly dispersed on the carbide support, interacts with the support via strong charge transfer, and more importantly shows excellent low-temperature water-gas shift reaction (LT-WGSR) activity. Oxidation treatment of the Au/MoCx catalysts leads to strong aggregation of Au nanoparticles and lower LT-WGSR activity. These results confirm that the SMSI effect is active in metal catalysts supported on carbides, which shows reversibility under alternative oxidation and carbonization treatment conditions. In-situ characterization methods have been used to study the evolution process during the carburization. It is proposed that epitaxy between Au and MoOxCy plays an important role in wetting and stabilization of Au on the carbide support.
The finding opens a new territory for the concept, which is of great significance for understanding of the SMSI effect and effective modulation of catalysis over carbide-supported metal catalysts.
The work was supported by the National Natural Science Foundation of China, the Strategic Priority Research Programme of the CAS, National Key Projects for Fundamental Research and Development of China, and Collaborative Innovation Center of Chemistry for Energy Materials (iChEM) (Text by DONG Jinhu).