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)(μ_(2)-O)(μ_(2)-H)(μ_(2)-OH)(η^(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.