Recently, Cell Publishing's flagship journal Chem Online published the latest progress of the research on the high-performance FePt-Fe3C interface low-platinum fuel cell electrocatalyst.
The commercial application of proton exchange membrane fuel cells is limited by the slow oxygen reduction kinetics of the cathode. Currently, the most effective strategy for improving the catalytic activity of oxygen reduction is through transition metals M (M=Fe, Co, Ni, Cu, etc.) with precious metals. Pt alloying regulation to optimize the bonding energy between the catalyst and oxygen-containing species, thereby enhancing 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 relative to surface catalysts. However, how to design a high-efficiency interface catalyst with a new interface enhancement mechanism is still a huge challenge. Due to its high electrical and thermal conductivity, excellent mechanical strength, hardness, chemical stability and corrosion resistance, transition metals in recent years Carbide gains considerable attention. Creating a new interface catalyst is still a huge challenge by combining PtM and transition metal carbides.
In order to solve these problems, Guo Shaojun, a team of Peking University School of Engineering, designed and developed a new type of dumbbell-shaped PtFe-Fe. 2C nanoparticles. This dumbbell-shaped PtFe-Fe2C nanoparticle is carbonized dumbbell shaped PtFe-Fe 3O4Nanoparticles were obtained (Fig. 1a). Electrochemical tests showed that the specific activity and mass activity of the catalyst for oxygen reduction in acidic media reached 3.53 mA cm, respectively. −2And 1.50 A mg −1Compared with commercial Pt/C, it is 11.8 and 7.1 times higher, and has excellent electrochemical stability. The activity of 5,000 cycles of catalyst is almost no attenuation. The research team further calculated that this unique structure has a novelty. The barrier-free interface electron transport mechanism is more conducive to the electrocatalytic reaction and thus the electrocatalytic activity (Fig. 1b). This barrier-free interface electron transport mechanism can also be extended to other electrocatalytic systems, such as electrocatalytic hydrogen evolution. Reaction and hydrogen peroxide electrocatalytic reduction. The specific activity of the catalyst for hydrogen evolution in an acidic medium reached 28.2 mA cm. −2, which is 2.9 times higher than commercial Pt/C. The detection limit of hydrogen peroxide electrochemical sensor based on the catalyst reaches 2nM. This work has guiding significance for the theoretical study of electrocatalysis and the development of new high-efficiency fuel cell electrocatalyst. The structural design of a generation of high-performance low-cost electrocatalysts provides new ideas.
Figure 1. a) Schematic diagram of synthesis; b) PtFe-
Fe 3O4Nanoparticles; c) PtFe-Fe
2C nanoparticle; d) DFT calculation
The work was completed by Guo Shaojun, a team of Peking University's College of Engineering. Guo Shaojun was the author of the paper, postdoctoral Lai Jianping and Dr. Huang Bolong of the Hong Kong Polytechnic University as co-first authors. The project received the National Natural Science Foundation, the Ministry of Science and Technology Key Research and Development Program and the Thousand Talents Program. And other project support.
