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

Abstract

The catalytic properties of 0.01mol% Pt/MoO3 reduced at 773K 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 60ml/min, the isomerization activity decreased with increasing reduction period, while the activity had a maximum at H2 flow rates of 15 and 30ml/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 15ml/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.