Great Breakthroughs Have Been Made In the Development of New Fuel Cell Catalysts

Commercial applications of proton exchange membrane fuel cells are limited by the slow oxygen reduction kinetics of the cathode.

Currently, the most effective strategy to improve the catalytic activity of oxygen reduction is to optimize the bonding energy between the catalyst and oxygen-containing species through the regulation of transition metal M (M=Fe, Co, Ni, Cu, etc.) and precious metal Pt alloying, so as to enhance the catalytic activity of oxygen reduction.

Recent studies have shown that interfacial catalysts can provide another effective way to enhance the catalytic activity of oxygen reduction compared with surface catalysts.

However, it is still a great challenge to design efficient interface catalysts with new interface enhancement mechanisms.

Due to their high conductivity and thermal conductivity, excellent mechanical strength, hardness, chemical stability and corrosion resistance, transition metal carbides have received considerable attention in recent years.

Creating a new interface catalyst through the combination of PtM and transition metal carbide remains a huge challenge.

To solve these problems, Guo Shaojun's team at Peking University school of technology designed and developed a new dumbbell shaped ptfe-fe2c nanoparticle.

The dumbbell shaped ptfe2c nanoparticles were obtained by carbonizing the dumbbell shaped ptfe3o4 nanoparticles.

Electrochemical tests showed that the specific activity and mass activity of oxygen reduction in acidic medium of the catalyst reached 3.53mAcm2 and 1.50Amg1, respectively, 11.8 and 7.1 times higher than commercial Pt/C, respectively, and had excellent electrochemical stability. The activity of 5,000 cyclic catalysts hardly decreased.

The team further calculated that this unique structure has a novel barrier free interface electron transport mechanism, which is more conducive to the electrocatalytic reaction to improve the electrocatalytic activity.

This barrier free interfacial electron transport mechanism can be extended to other electrocatalytic systems such as electrocatalytic hydrogen evolution and electrocatalytic reduction of hydrogen peroxide.

The specific activity of hydrogen evolution of the catalyst in acidic medium reached 28.2mAcm2, 2.9 times higher than commercial Pt/C, respectively.

Based on the catalyst, the detection limit of the electrochemical sensor of hydrogen peroxide reaches 2nM.

This work is of guiding significance to the theoretical study of electrocatalysis and the development of new high efficiency fuel cell electrocatalysts as well as provides a new idea for the structural design of the next generation of high performance and low cost electrocatalysts.

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