Spectroscopic identification of water splitting by neutral group 3 metals

Spectroscopic study of water splitting by neutral metal clusters is crucial to understanding the microscopic mechanism of catalytic processes but has been proven to be a challenging experimental target due to the difficulty in size selection. Here, we report a size-specific infrared spectroscopic study of the reactions between neutral group 3 metals and water molecules based on threshold photoionization using a vacuum ultraviolet laser. Quantum chemical calculations were carried out to identify the structures and to assign the experimental spectra. All the M 2 O 4 H 4 (M = Sc, Y, La) products are found to have the intriguing M 2 ( & mu;2 -O)( & mu;2 -H)( & mu;2 -OH)( & eta;1 -OH) 2 structures, indicating that the H -OH bond breaking, the M -O/M -H/M -OH bond formation, and hydrogen production proceed efficiently in the reactions between laser-vaporized metals and water molecules. The joint experimental and theoretical results on the atomic scale demonstrate that the water splitting by neutral group 3 metals is both thermodynamically exothermic and kinetically facile in the gas phase. These findings have important implications for unravelling the structure-reactivity relationship of catalysts with isolated metal atoms/clusters dispersed on supports. & COPY; 2023 Published by Elsevier B.V. on behalf of Chinese Chemical Society and Institute of Materia Medica, Chinese Academy of Medical Sciences.