Directly Sulfonated Carbon Nanofibers to Improve Single-Cell Performance of Pt/CNFs–SO₃H Catalyst

Due to the high cost of electrocatalysts, mass manufacturing of fuel-cell driven cars is a challenge. In the catalytic layer, the Nafion ionomer allows for minimal Pt consumption. Various carbon compounds were produced and their catalytic activities for oxygen reduction process were examined in this study. Results suggest that Pt/CNFs have the best performance due to their good electrical conductivity, rich surface defects, and the ease with which CNFs may be mass transported. As a result, CNFs were chosen to be sulfonated immediately by concentrated sulfuric acid at high temperatures. After sulfonation, the sulfonic acid functional group (–SO3H) was identified in the spectrum of Fourier transform infrared spectroscopy at a wavenumber of 1033 cm−1, and a Pt/CNFs–SO3H electrocatalyst was made using the ethylene glycol technique. After 10,000 cycles, the linear sweep voltammetry curve barely changes, and the current density can sustain 95% after 6 hours of chronoamperometric testing at 0.6 V. Pt/CNFs–SO3H can produce a maximum power density in a hydrogen/air single-cell is 397.5 mW cm−2, compared with 353.2 mW cm−2 of Pt/CNFs, a 12.5% increase, demonstrating CNFs–SO3H may significantly improve proton transportation capabilities.