Vacuum-Field Catalysis: Accelerated Reactions by Vibrational Ultra Strong Coupling

In conventional catalysis, the reactants interact with specific sites of the catalyst in such a way that the reaction barrier is lowered by changing the reaction path, causing the reaction rate to be accelerated. Here we take a radically different
approach to catalysis by ultra-strongly coupling the vibrations of the reactants to the infrared vacuum electromagnetic field. To demonstrate the possibility of such
vacuum-field catalysis (or cavity catalysis), we have studied hydrolysis reactions under the vibrational ultra strong coupling (V-USC) of the OH stretching mode of water to a Fabry-Pérot microfluidic cavity mode. This results in a giant Rabi splitting energy (92 meV), indicating the system is in the V-USC regime. We have found that V-USC water enhances the hydrolysis reaction rate of cyanate ions by
10²-fold and that of ammonia borane by 10⁴-fold. This catalytic ability is found to depend upon the coupling ratio of the vibrational light-matter interaction. Given the vital importance of water for life and human activities, we expect that our finding not only offers an unconventional way of controlling chemical reactions by vacuum-field catalysis but also brings a fresh perspective to science and technology.