Synthesis of low cost cathode electrocatalyst Pt-Ni/CAB using DMSO as a solvent for low temperature proton exchange membrane fuel cell application

In the present study, low cost platinum based bimetallic electrocatalyst Pt-Ni/C_AB with varying Pt to Ni atomic ratios 3:1, 1:1, and 1:3 were successfully synthesized for oxygen reduction reaction (ORR) of the developed proton exchange membrane fuel cell (PEMFC). The solvothermal process was adopted for the synthesis of Pt-Ni(3:1)/C_AB, Pt-Ni(1:1)/C_AB, and Pt-Ni(1:3)/C_AB using dimethyl sulfoxide (DMSO) as solvent at a temperature of 190°C which is very close to the boiling point. The Pt-Ni/C_AB exhibited the highest activity for the ORR in half-cell and single cell PEMFC performance. The electrocatalysts Pt-Ni(1:3)/C_AB appeared with smallest crystalline FCC structures having crystallite size of 8.33 nm. The transmission electron microscopy (TEM) analysis also show that the Pt-Ni(1:3)/C_AB has smallest particle size of 1.67 ± 0.45 nm. The cyclic voltammetry (CV) analysis shows Pt-Ni(1:3)/C_AB electrocatalyst offers less activation loss at ORR peak at a potential of 0.16 V as compared to Pt-Ni(3:1)/C_AB (ORR peak – 0.12) and Pt-Ni(1:1)/C_AB (ORR peak – 0.11). The synthesized Pt-Ni(1:3)/C_AB produced a maximum power density of 18.86 mW/cm² at a maximum current density of 44.8 mA/cm² with an open-circuit voltage of 0.914 V at a room temperature of 33°C. The power density improved around 1.34 times when the cell temperature was raised from 33 to 70°C. The Pt-Ni(1:3)/C_AB cathode electrocatalyst could be used as economical to substitute costly commercial pure platinum based electrocatalyst.