Preparation of High-Platinum-Load Platinum-on-Carbon Catalysts by Liquid-Phase Pressurized Hydrogen Reduction Using Platinum Nitrate Impregnation and High Specific Surface Area Carbon Carriers

Abstract

High Pt-load catalysts can be used to prepare thin catalytic layers and high-energy-density proton-exchange-membrane fuel cell cathodes for practical applications. However, because high Pt loads agglomerate Pt nanoparticles on carrier surfaces, the batch preparation of high Pt-load catalysts possessing both high activity and high Pt nanoparticle dispersibility is important for practical applications. In this study, high Pt-load Pt/C catalysts were prepared using a platinum nitrate precursor and the high specific surface area Ketjenblack EC600JD carbon carrier via impregnation and liquid-phase hydrogenation reduction. In the catalyst, the average Pt nanoparticle size was 2.30 nm. The electrochemically active surface area of the Pt/C_EC600JD catalyst was 63.91 m² g_Pt^–1, and its mass activity (MA) was 0.35 A mg_Pt^–1 at 0.9 V (versus a reversible hydrogen electrode), which is 1.4 times that of commercial 50% Pt/C_TKK, as measured using a rotating disk electrode. After 20 000 accelerated durability test cycles, the MA of the Pt/C_EC600JD catalyst was 1.7 times that of 50% Pt/C_TKK under the same experimental conditions. The catalyst synthesized using platinum nitrate and EC600JD showed excellent activity and can be used for practical electrocatalytic applications.