CO-promoted N2 adsorption on copper atoms

Abstract

Reactions of laser-ablated copper atoms with carbon monoxide and dinitrogen in excess argon have been investigated by matrix-isolation infrared spectroscopy. The NNCuCO and (NN)₂CuCO complexes, as well as copper carbonyls, are formed as reaction products during sample deposition and further annealing whereas no copper dinitrogen complexes were observed. These carbonylcopper dinitrogen complexes are characterized on the basis of the results of the isotopic substitution and the reagent concentration change. Density functional theory calculations of the geometry structures, vibrational frequencies, relative absorption intensities, and isotopic shifts strongly support the experimental assignments. The experimental results reveal promoted adsorption of N₂ on Cu atoms by preadsorbed CO. The theoretical results for reaction characteristics between the coadsorbed CO and N₂ agree with the experimental findings. The joint investigations provide insights with regard to CO and N₂ cooperative adsorption effects and consequent reaction mechanisms.