Modern alchemy, where 30 kinds of metal elements are mixed with carbonated water to synthesize complex nanoparticles in 1 minute, has become a reality. This is because carbon dioxide dissolved in water acts as a link that binds metals together.
Professor Cho Seung-ho and Lee Seok-bin of the Department of New Materials Engineering at Ulsan Institute of Science and Technology (UNIST) and Professor Kim Jung-hwan of the Graduate School of Semiconductor Materials and Components announced on the 4th that they have developed a technology to synthesize “ultra-high entropy nanomaterials” containing 30 kinds of metal elements using carbon dioxide in 1 minute with researchers from Cologne University in Germany and Purdue University in the US.
High entropy materials are materials containing a mixture of 5 or more metals, and are attracting attention in advanced industries such as batteries and semiconductors due to their superior durability and catalytic activity compared to single metals. However, since the metal atoms are different in size, a high temperature and pressure of several thousand degrees (℃) was required to mix several types at once. This is the main cause of increasing production costs and hindering mass production.
The research team developed a technology that can easily synthesize carbon dioxide at room temperature and pressure. When carbon dioxide dissolves in water, it changes to a carbonic acid ion, and the principle is that this carbonate ion acts as a link connecting different metals.
The manufacturing process is simple. After injecting carbon dioxide gas into the water to make carbonated water, hydroxide (OH?) When added, carbon dioxide dissolved in water turns into carbonate ions that are easy to bind to metals. In this state, when a solution containing 30 ionic metal raw materials is poured and stirred for 1 minute, carbonate ions quickly connect various metal ions into one to synthesize powdery nanomaterials.
Using this method, the research team synthesized “metal carbonate nanoparticles” containing a mixture of neodymium (Nd), a rare earth metal for permanent magnets, and up to 30 types of metals, including copper and iron, which are transition metals. According to the existing law for predicting mixed structures in crystals, rare earth metals with large original diameters and transition metals with small diameters are difficult to mix well. Also, as a result of analyzing the synthesized material with an electron microscope, etc., a unique structure with no long-range regularity was observed, unlike ordinary crystals.
Professor Lee Seok-bin explained, “This disordered structure can be beneficial in improving catalytic reactions and energy storage efficiency,” and “based on this synthesis technology, we will explore and develop various material combinations such as catalysts for hydrogen production and electrode materials for secondary batteries.”
Professor Cho Seung-ho said, “Achieving multi-component metal synthesis, which was only possible in harsh environments of high temperature and pressure, will dramatically reduce manufacturing costs, but also contribute to reducing carbon dioxide, which is a greenhouse gas,” said Professor Cho Seung-ho. “The ultimate goal is to develop a material synthesis method with no composition restrictions at all through follow-up research.”
Professor Sanjay Mathur (Sanjay Mathur) of the Department of Chemistry at the University of Cologne, Germany, and Professor Haiyan Wang (Haiyan Wang) of the Department of New Materials Engineering at Purdue University, USA, participated as first authors, a researcher Kim Miri from the UNIST Department of New Materials Engineering, Dr. Kim Min-ji, and researcher Yizhi Zhang (Yizhi Zhang) of the Department of New Materials Engineering at Purdue University. The research results were published online on November 21 in Nano Letters (Nano Letters), a well-known international journal in the field of nano science and technology.
