Preparation Procedures of Pt-Decorated SnO2 Electrocatalysts on Conductive Fillers
First, we have reexamined the procedure for the preparation of SnO2. Previously, SnO2/VGCF and SnO2/AB were synthesized via the ammonia co-precipitation. In this process, due to heat treatment required at a high temperature (e.g. 600oC), the particles of SnO2 were agglomerated. We thus introduced a homogeneous precipitation procedure using microwaves which requires no heat treatment at a high temperature. Consequently, the BET specific surface area of SnO2becomes one order of magnitude larger.
Second, we have adjusted the loading of SnO2 for the conductive fillers. The BET specific surface area of SnO2/VGCF becomes larger with increasing SnO2 loading. However, their electrochemical activity decreased for too high SnO2 loading, due to its lower electrical conductivity. In addition, the catalytic activity was improved by heat treatment to 200 or 400oC. The details on the catalytic activity increase by optimizing SnO2loading and heat treatment temperature will be presented at the meeting.
 F. Takasaki et al., J. Electrochem. Soc., 158(10) B1270 (2011).