Catalysts facilitate various chemical reactions and among them, catalysts prepared from alloys of multiple metals exhibit activities that are not obtained with those that are single metal-based. This has meant that catalysts composed of various combinations have been studied. However, it has been difficult to prepare an alloy with a uniform distribution of 10 or more elements, as combinations of different elements are difficult to mix, akin to the difficulty experienced in mixing water and oil.
A research group including members from the School of Environmental Science and Engineering at the Kochi University of Technology, Assistant Professor Zexing Cai, Professor Takeshi Fujita, and others, has succeeded in developing a nanoporous ultra-high-entropy alloy that contains a uniform distribution of 14 elements and possesses a sponge-like structure in which nanosized pores are randomly connected. The catalyst produces the aluminum alloy containing 14 elements, de-alloys it by preferentially dissolving aluminum in an alkaline solution, and aggregates elements apart from aluminum. Mass production is possible because the catalyst only melts the alloy.
The research group used the obtained ultra-high-entropy alloy as an electrode catalyst for the electrolysis of water and confirmed that it delivered better performance and durability than platinum (Pt) and iridium oxide, which are used as benchmarks used to compare catalytic performance. Since this ultra-high-entropy alloy is composed of various elements, it could find wide application as a catalyst that optimally utilizes its pluripotency, in addition to facilitating the electrolysis of water. This success in the simple development of an ultra-high-entropy alloy is expected to enable the combination of elements in a customized manner to obtain optimum catalysts for various reactions.
