Preparation and characterization of mesoporous carbon-supported Pt nanocatalyst and its stability under strong acidic solutions

Pt/C catalyst was prepared by the formic acid reduction method (FARM) using mesoporous carbon supports with submicron-scale particle size, which was synthesized by the nano-replication technique using mesoporous silica (MSU-H) as templates. The average size of the Pt particles, calculated from the Pt(1 1 1) peak by Scherrer equation, was found to be 3.3 nm. The chemical stabilities of Pt/C catalysts and polymer-coated Pt/C catalysts were examined in distilled water and in strong acidic solutions such as H₂SO₄ and HClO₄. The release amount of Pt in distilled water was found to be at trace levels (<3 ppb), which is close to the detection limits of ICP-AES. However, the Pt release greatly increased with time in both H₂SO₄ and HClO₄ solutions and reached a few percent levels in a week. On the other hand, a PVP/PEI-coated Pt/C catalyst showed much better stability that the Pt release was about 0.5% in 3 M HClO₄ for a week, compared with that of a pristine Pt/C catalyst.