A Highly Stable Bimetallic Transition Metal Phosphide Catalyst for Selective Dehydrogenation of n‐Heptane

In this work, we demonstrate RuP2‐MoP catalysts being highly stable and selective for the dehydrogenation of long‐chain alkanes like n‐heptane. Compared to a monometallic MoP catalyst, the bimetallic system substantially increases n‐heptene selectivity from 40 % towards 80 %. This effect can be traced back to a reduced surface acidity, suppressing the competitive hydrogenolysis reaction. The active transition metal phosphide is, furthermore, compared to its phosphorous‐free RuMo‐counterpart. As revealed by STEM‐EDX investigations, incorporation of phosphorous results in the formation of separated metal phosphide clusters instead of an intermetallic alloy. In the dehydrogenation of n‐heptane the phosphorous modification clearly avoids catalyst deactivation and maintains the high n‐heptene selectivity. X‐ray diffraction, elemental analysis and STEM‐EDX further reveal that catalyst coking and the formation of less active molybdenum carbide phases is effectively suppressed by phosphorous incorporation, making RuP2‐MoP an attractive system for selective dehydrogenation of long‐chain alkanes.