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 H-2 in the reduction process. At a H-2 flow rate of 60 ml/min, the isomerization activity decreased with increasing reduction period, while the activity had a maximum at H-2 flow rates of 15 and 30 ml/min. Pt/MoO3 was more deeply reduced by the larger flow rate of H-2 as well as by the longer reduction period. The surface area of Pt/MoO3 was enlarged by H-2 reduction, and its surface area varied with the reduction conditions. The largest surface area of 340 m(2)/g was obtained at a H-2 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 H-2 flow rate yielded the catalyst with larger surface area and higher isomerization activity. (C) 2013 Elsevier B.V. All rights reserved.