Physical and catalytic properties of Pt/MoO3 reduced at different H2 flow rates

• H2 reduction of Pt/MoO3 at 773 K yielded porous MoOx.
• MoOx obtained by reduction with a slow rate had the largest surface area of 340 m2/g and the highest isomerization activity.
• The reduction rate depended on the flow rate of H2.

The catalytic properties of 0.01 mol% Pt/MoO3 reduced at 773 K for heptane isomerization were studied. The catalytic activity was affected not only by the reduction period but also by the flow rate of H2 in the reduction process. At a H2 flow rate of 60 ml/min, the isomerization activity decreased with increasing reduction period, while the activity had a maximum at H2 flow rates of 15 and 30 ml/min. Pt/MoO3 was more deeply reduced by the larger flow rate of H2 as well as by the longer reduction period. The surface area of Pt/MoO3 was enlarged by H2 reduction, and its surface area varied with the reduction conditions. The largest surface area of 340 m2/g was obtained at a H2 flow rate of 15 ml/min. The isomerization activity and the surface area were dependent on average Mo valence. When the surface area and the isomerization activity were compared at a certain Mo valence, reduction at smaller H2 flow rate yielded the catalyst with larger surface area and higher isomerization activity.

Figure optionsDownload high-quality image (83 K)Download as PowerPoint slide