Transition metal silicides: fundamentals, preparation and catalytic applications

Abstract

Transition metal silicides as typical intermetallic compounds are important in microelectronics and ceramics because of their good electrical conductivity, high chemical inertness and thermal stability. Recently, transition metal silicides have become indispensable constituents in catalytic systems for a variety of applications due to their specific crystal and electronic structures different from those of their component metals. In this review, an overview of recent development in transition metal silicide nanomaterials as catalysts is presented. The chemical and physical properties of metal silicides are briefly discussed. The properties of transition metal silicides depend to a large extent on the way that they were made or processed, this being a consequence of different structures. The synthetic strategies for transition metal silicides from traditional high-temperature methods to emerging technology for nanomaterials are also discussed. Then we will summarize the application of transition metal silicides as heterogeneous catalysts and explain their excellent selectivity to the intermediate product in hydrogenation reactions and high stability in the harsh environment of hydrotreatment reactions. Furthermore, CNT growth processes over metal silicides catalysts are presented. The use of transition metal silicides as photocatalysts and electrocatalysts is also discussed. Finally, some key challenges and issues which should not be ignored during the development of transition metal silicide catalysts are pointed out. These strategies and challenges of transition metal silicides promote the investigation of the surface catalytically active centers and confirm the structure–catalytic property relationships.