Study on the oxygen reduction reaction performance of high Pt load catalyst supported on carbon black modified by conductive polymer polyethylene dioxythiophene in proton exchange membrane fuel cells

In situ polymerization of ethylene dioxythiophene (EDOT) on Keqin Black EC-300 J (CB) to obtain a support (PEDOT@C) with polyethylene dioxythiophene coating on CB. By coating PEDOT on CB, the structural characteristics and surface functionalization degree of CB can be optimized. Then, highly dispersed Pt nanoparticles (NPs, 3–5 nm) was prepared by reducing chloroplatinic acid using an improved sodium borohydride reduction method and loaded onto PEDOT@C to obtain a high loading amount of 40 wt% Pt/PEDOT@C catalyst. The optimization of PEDOT@C structure can strengthen the dispersion of Pt NPs, increase the exposed active sites, thus improve the Electrochemical Active Surface area (ECSA) of Pt/PEDOT@C catalyst (reaching 114.28 m²/g), which is 127.5 % and 60.01 % higher than that of JM Pt/C and Pt/CB, respectively. Meanwhile, the Mass activity (MA) of Pt/PEDOT@C catalyst is 0.142 A/mg Pt, which is 38 % and 0.7 % higher than JM Pt/C and Pt/CB, respectively. The stability of Pt/PEDOT@C catalyst is also significantly improved. After accelerated testing, the ECSA loss is 8.33 %, much lower than the 17.33 % and 19.4 % of JM Pt/C and Pt/CB, respectively; the loss of MA is 9.8 %, much lower than the 41.7 % and 18.4 % of JM Pt/C and Pt/CB, respectively. The Pt/PEDOT@C catalyst also has the highest power density (1470 mW/cm²), indicating that the PEDOT modification strategy helps to improve the catalytic performance of the catalyst. The results of this study will promote the development of PEMFCs power sources.