Fluorinated bimetallic nanoparticles decorated carbon nanofibers as highly active and durable oxygen electrocatalyst for fuel cells

The low activity and durability are still the critical barriers for non-precious metal electrocatalyst, mainly involving M-N/C (M = Fe, Co, Mn et al), applied in fuel cell. Constructing bimetallic sites has been explored as an effective method to boost the performance of the catalyst for the synergistic effect between metal atoms. However, this synergistic effect is always suppressed in acidic conditions and results in unstable catalytic performance. Here we create novel fluorinated iron (Fe) and cobalt (Co) bimetallic nanoparticles distributed on nitrogen-doped carbon nanofibers (CNFs) for oxygen reduction reaction (ORR). The fluorination strongly increased the charge density of the bimetallic catalyst and resulted in a remarkable catalytic performance with the half-wave potential of 804 mV in 0.1 M HClO₄ and 1.6 times power density improvement for the proton exchange membrane fuel cell device. Importantly, the chemical and mechanical robust CNFs support improved the electric conductivity and stability of bimetallic catalysts, which leads to an ultra-stable electrocatalyst. The fuel cell voltage can keep stable even after 110 h, instead of the continuingly decrease in the traditional M-N/C.