The emergence of Heusler alloy catalysts

For over a century, Heusler alloys (X₂YZ; X, Y: transition metals, Z: typical metals) have attracted attention as magnetic materials. Nowadays, they are also popular as thermoelectric and shape memory materials. However, until very recently, Heusler alloys had been almost unknown as catalysts. We conceived that they could be ideal candidates for catalysts because (1) they have so many elemental sets and (2) they can be partially substituted with other elements (e.g. X₂YZ_1–xZ’_x) in many cases. We first investigated a variety of Heusler alloys as catalysts and then discovered effective catalysts without precious metals for the selective hydrogenation of alkynes based on the aforementioned feature (1) and demonstrated a systematic tuning of catalytic properties by applying the feature (2). Heusler alloy catalysts have also recently been studied by other groups; hence, this traditional alloy group is becoming a new stream in terms of catalysis. In this article, we review the current progress on Heusler alloy catalysts and describe their future prospects.