Dinitrogen Activation by Heteronuclear Metal Carbide Cluster Anions Y1‐3CoC1,2−: An Experimental and DFT Study

Abstract

AbstractMass spectrometry was used to observe the reactions between Y−Co heteronuclear metal carbide cluster anions Y1‐3CoC1,2− and N2 at room temperature. Y2CoC1,2− can produce Co ejection products, in which Y2CoC− also has N2 association products; YCoC2− and Y3CoC− only generate N2 association products, while YCoC− and Y3CoC2− are inert to N2. Detailed reaction pathways were obtained through density functional theory calculations, which reasonably explain the experimental phenomena. Co is superior to Y as the electrophilic reaction site in the clusters and is the preferential initial adsorption site for N2. Some crucial steps were identified, including N−N dissociation, CC−N formation, C−CN dissociation, and C−N formation. The energy barriers of these steps are closely related to the coordination mode of N/N2 and C/C2 in clusters. Two indicators, the N−N bond length and the Mayer bond order, were utilized to describe the activation degree of the N−N bond. Analyses on the density of states and the frontier molecular orbitals reveal the electronic structures of key intermediates for N−N dissociation. The reaction mechanisms of N2 activation on Y−Co carbide clusters obtained may lay a preliminary foundation for the further development of catalysts for nitrogen reduction reaction (NRR).