Development of highly active and durable Pt catalysts covered with silica

在聚合物电解质燃料电池（PEFC）中，由于Pt催化剂需要在非常苛刻的条件下工作，如低pH值、高正电位和氧气气氛，阴极Pt催化剂由于Pt金属颗粒的聚集和溶解以及随后的沉积而失活。我们用几纳米厚的二氧化硅层覆盖碳载Pt催化剂，以提高Pt金属在阴极条件下的耐久性。用二氧化硅覆盖的Pt催化剂对氧还原反应表现出高活性和优异的耐久性。此外，二氧化硅的覆盖可用于开发高活性和耐用的Pt-Co合金催化剂。

Pt catalysts at cathode in polymer electrolyte fuel cells (PEFC) are deactivated due to the aggregation of Pt metal particles and the dissolution and subsequent deposition of Pt metal, because the Pt catalysts should work under very severe conditions such as low pH, highly positive potential and oxygen atmosphere. We covered carbon-supported Pt catalysts with silica layers a few nanometers thick in order to improve the durability of Pt metal under the cathode conditions. The Pt catalysts covered with silica showed high activity and excellent durability for the oxygen reduction reaction. In addition, the coverage with silica can be applied to the development of highly active and durable Pt-Co alloy catalysts.