As a group of ternary intermetallic compounds, Heusler alloys (X2YZ) can be unique catalysts. Heusler alloys are suitable as a platform to reveal common rules for catalysis by intermetallic compounds because the catalytic properties of various X2YZ compounds, including partially substituted alloys (e.g., X2YZ1−xZ′x), can be investigated under the same crystal structure. Previous studies on Heusler alloys have reported that the irreversible oxidation of catalysts occurs during the reaction with O2and H2O and that their activity for alkyne hydrogenation does not correlate with the d-band center. For the use of Heusler alloys as a platform to discuss catalytic properties in association with electronic structures of intermetallic states, durability against oxidation should be revealed, and the correlation between the activity and d-band center should be verified. In this study, Co2YZ (Y = Mn or Fe, Z = Ga or Ge) Heusler alloy catalysts for the dehydrogenation of 2-propanol were investigated. The oxygen atom in 2-propanol molecules and tiny amounts of O2 and H2O impurities in liquidous reagents were suitable as mild oxidants to evaluate the durability limit: Co2FeGe was durable, whereas Mn and Ga were oxidized. The initial activity correlated with the d-band center. These findings are beneficial for the future use of Heusler alloys not only as a platform but also for practical catalysts.
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