A highly stable bimetallic transition metal phosphide catalyst for selective dehydrogenation of n‐heptane

In this work, we demonstrate RuP2-MoP catalystsbeing highly stable and selective for the dehydrogenation of longchainalkanes like n-heptane. Compared to a monometallic MoPcatalyst, the bimetallic system substantially increases n-hepteneselectivity from 40% towards 80%. This effect can be traced backto a reduced surface acidity, suppressing the competitivehydrogenolysis reaction. The active transition metal phosphide is,furthermore, compared to its phosphorous-free RuMo-counterpart.As revealed by STEM-EDX investigations, incorporation ofphosphorous results in the formation of separated metalphosphide clusters instead of an intermetallic alloy. In thedehydrogenation of n-heptane the phosphorous modificationclearly avoids catalyst deactivation and maintains the highn-heptene selectivity. X-ray diffraction, elemental analysis andSTEM-EDX further reveal that catalyst coking and the formationof less active molybdenum carbide phases is effectivelysuppressed by phosphorous incorporation, making RuP2-MoP anattractive system for selective dehydrogenation of long-chainalkanes