New Operating Principle of Metal Catalysts Revealed; Performance Improvements Expected

[Financial News] A new operating principle of metal catalysts, which are essential to chemical production and the energy industry, has been uncovered. The discovery is expected to help improve the accuracy of predictions about catalyst performance and contribute to improvements.
The Ministry of Science and ICT said on the 30th that a joint research team from the Institute for Basic Science (IBS) Center for Quantum Nanoscience and the Max Planck Institute for Multidisciplinary Sciences had established that atomic structures several nanometers (nm) away from where molecules bind on a metal catalyst surface can also affect the strength of chemical bonds.
The research was conducted with support from the MSIT’s program for IBS research centers, and the findings were published in the international scientific journal Science at 3 a.m. on October 30.
According to the research team, metal catalysts are substances that accelerate chemical reactions and are used in a range of industries, including the production of chemicals and fuels. 
Chemical reactions using metal catalysts begin when molecules, the reactants, attach to a metal surface. The strength of the bond between the molecule and the metal is a key factor determining how smoothly the chemical reaction proceeds afterward. Therefore, understanding how molecules bind to metal surfaces is important for predicting and improving catalyst performance.
The researchers experimentally confirmed that long-range electronic effects can alter the strength of the bond between a molecule and a metal on the surface of a metal catalyst. To do so, they used platinum surfaces whose atoms were layered to form steps. They created platinum surfaces with different distances between the atomic steps, then precisely measured and compared the strengths of the bonds formed between the metal and ammonia (NH3), carbon monoxide (CO), and nitric oxide (NO) molecules.
As a result, they found that bond strength varied with the distance to a neighboring step, even when the structures at the points where molecules attached were similar. The difference in bond energy was up to about 0.2 electronvolts (eV), enough to cause a substantial change in bond stability. The characteristic distance over which long-range effects appeared was about 4–7 nanometers, depending on the molecule—roughly the length of tens of atoms lined up in a row.
The researchers also identified the cause of this phenomenon. In metals, vast numbers of electrons are spread over a wide area rather than remaining around specific atoms, forming what is like a vast “sea of electrons.” When a molecule attaches to a metal surface, its electrons interact with this sea of electrons, making it susceptible to the effects of atomic structures far away. In other words, chemical bonds between molecules and metals can be affected by electronic interactions spanning a wide area.
The researchers also proposed the “Frontier Orbital-Band Model,” which combines the concept of molecular orbitals in chemistry with that of electron bands in physics, to explain why long-range effects vary from one molecule to another. The model explains that each molecule has different electronic-state characteristics and interacts with different electronic states inside the metal, causing long-range effects to vary by molecule even on the same metal surface.
Dmitriy Borodin, group leader at the IBS Center for Quantum Nanoscience and co-corresponding author, said, “In the past, catalyst development relied on lengthy experiments and trial and error, but now it is moving toward predicting and designing desired properties based on the principles of chemical reactions.” He added, “We expect this research to broaden our understanding of chemical bonding and contribute to more sophisticated calculations and more efficient catalyst design.”

[email protected] Yeon Ji-an Reporter