The effect of supported Rh, Ru, Pt or Ir nanoparticles on activity and selectivity of ZrO2-based catalysts in non-oxidative dehydrogenation of propane

A series of catalysts on the basis of ZrO2, LaZrOx and YZrOx with supported Rh, Ru, Pt or Ir nanoparticles (NPs) were prepared. They were tested in the non-oxidative dehydrogenation of propane (PDH) to elucidate the effects of (i) the kind of supported metal and its loading, (ii) the size (1 nm or 5 nm) of NPs, (iii) metal oxide promoter for ZrO2 and (iv) reaction temperature on PDH performance. Although the metals did not directly participate in propene formation, they improve catalyst activity through (i) promotion of Zrcus (cus means coordinatively unsaturated) formation and (ii) acceleration of hydrogen formation. The kind of metal was also established to be decisive for propene adsorption. The latter property has a negative effect on catalyst activity and propene selectivity. The most active Rh/YZrOx catalyst with 0.05 wt% Rh revealed about 1.6 times higher propene formation rate than a commercial-like K-CrOx/Al2O3 or the state-of-the-art Ru/YZrOx.