Direct methanol fuel cell (DMFC) is a new type of efficient and clean energy, but the methane oxidation reaction (MOR) that it relies on is very slow. During the operation of fuel cells, commonly used platinum catalysts are affected by intermediate chemical products and the effective active surface area will gradually decrease. Therefore, gold-based alternatives are attractive. However, like platinum, gold is too scarce and expensive to be suitable for large-scale use in automobiles.
In this research, Yusuke Yamauchi, a researcher at the University of Queensland, proposed a simple method for preparing gold-nickel nanofilms, which can not only reduce the amount of gold, but also optimize the catalytic activity and stability. He said: "The catalytic activity of gold is very interesting. Under normal conditions, the reaction is not easy to occur. After the formation of nanostructures, it can promote various oxidation reactions in low temperature environments. Because platinum does not have long-term durability, gold It is expected to replace platinum as a new-generation catalyst. "Other universities participating in this research include: Waseda University, National Institute of Materials Science, Wollongong University, Tianjin University, Qingdao University of Science and Technology, and Kyung Hee University in South Korea.
Nanostructured metals, especially nanoporous metals, can be synthesized by a variety of methods, but most of the related synthesis processes are complicated and need to meet harsh conditions. In this case, Yamauchi and colleagues developed a method called "soft-templated". In a solution containing polymer micelles, the metal precursor is electrochemically reduced. The micelle acts as a template or mold to form pores in the metal film, which can then be easily removed with a solvent. He said: "Our method is very simple and does not take time. Through a simple preparation process, a mesoporous bimetallic gold-nickel film with excellent electrocatalytic activity can be synthesized."
Using this simple and direct process, a porous Au-Ni metal thin film with uniform mixing can be prepared with a pore diameter of 28 nm, which provides sufficient space for the reaction of other chemical substances. Yamauchi pointed out: "The metal frame of this kind of material is stable and highly conductive, which is very suitable for electrochemical applications. Due to the synergistic effect of the modified chemical and electronic properties, mesoporous bimetallic alloys are considered to have Better catalytic activity. "
The research team believes that in the methane oxidation reaction, Au-Ni porous metal membranes exhibit higher electrocatalytic activity than other gold-based catalysts and are very suitable for direct methanol fuel cells. Moreover, the method proposed by this research is applicable to various metals. Yamauchi said: "In terms of optics, energy storage and biosensing, this nanostructured material opens up broad application prospects. This is a very attractive opportunity and deserves further exploration."