Commercially available Pt metal catalysts supported on carbon black (Pt/CB) for polymer electrolyte fuel cell (PEFC) cathodes were covered with silica layers to improve their durability under the severe cathode operating conditions. The Pt metal particles in the Pt/CB catalyst grew in size during the accelerated durability tests (potential cycling between 0.6 and 1.0 V vs. RHE in an aqueous HClO₄ electrolyte). Thus, the Pt/CB catalyst was seriously deactivated for the oxygen reduction reaction over the course of the durability tests. In contrast, the silica layers, which wrapped around the Pt metal particles in the silica-coated Pt/CB catalyst, prevented the migration of the Pt metal particles on the carbon supports and the diffusion of Pt cations out of the silica layers. Thus, the silica-coated Pt/CB catalysts maintained a high activity for the oxygen reduction reaction over the course of the durability tests. In addition, the silica-coated Pt/CB prepared from methyltriethoxysilane showed a higher activity than that prepared from tetraethoxysilane. The porous structures and hydrophobicity of silica prepared from methyltriethoxysilane promoted the diffusion of oxygen and water molecules in the silica layers of the silica-coated Pt catalysts.

负载在用于聚合物电解质燃料电池（PEFC）阴极的炭黑（Pt / CB）上的市售Pt金属催化剂上覆盖有二氧化硅层，以提高其在严酷的阴极操作条件下的耐久性。Pt / CB催化剂中的Pt金属颗粒在加速耐久性试验期间（在HClO ₄水溶液中，相对于RHE的电势循环在0.6和1.0 V之间）增长了电解质）。因此，在耐久性试验过程中，Pt / CB催化剂因氧还原反应而严重失活。相反，在二氧化硅涂覆的Pt / CB催化剂中包裹在Pt金属颗粒周围的二氧化硅层阻止了Pt金属颗粒在碳载体上的迁移以及Pt阳离子从二氧化硅层中扩散出来。因此，在耐久性试验过程中，二氧化硅涂覆的Pt / CB催化剂对氧还原反应保持了高活性。另外，由甲基三乙氧基硅烷制备的二氧化硅涂覆的Pt / CB显示出比由四乙氧基硅烷制备的更高的活性。