Development of Highly Efficient Catalysts for DeNOx and Alkane Dehydrogenation Based on Multimetallic Alloys

Alloying is one of the most effective methodologies for modifying the catalytic performance of metal catalysts, and conventional methods have developed various useful catalysts containing solid solution alloys or intermetallic compounds1). However, recent research has suggested that much more efficient catalysts using bimetallic materials is difficult, as there are limits to further improvement of activity and function based on only two metal elements2). For a binary intermetallic compound AnBm, the atomic ratio n : m is typically fixed to some integer values such as 3 : 1, 2 : 1, and 1 : 1. Moreover, the crystal structure depends on the atomic ratio, so fine tuning of the electronic and geometric structure is difficult. Therefore, a novel methodology and materials are desired to introduce more flexibility and expandability into catalyst design2). We have systematically studied the catalytic chemistry of ternary alloys based on metallurgy and nanoscience2). We discovered that extremely high-performance catalysts that greatly exceed conventional binary alloys can be prepared by incorporating three types of metal elements according to appropriate design guidelines. This review introduces two catalyst design concepts for the construction of multi-metallic surface reaction environments effective for deNOx reactions and alkane dehydrogenation, which are increasingly used worldwide.