Facile N≡N Bond Cleavage by Anionic Trimetallic Clusters V_3−xTa_xC₄⁻ (x=0–3): A DFT Study

Abstract

Activation of N 2 on anionic trimetallic V 3À x Ta x C 4 À (x = 0-3) clusters was theoretically studied employing density functional theory. For all studied clusters, initial adsorption of N 2 (end-on) on one of the metal atoms (denoted as Site 1) is transferred to an of end-on: side-on: side-on coordination on three metal atoms, prior to N 2 dissociation. The whole reaction is exothermic and has no global energy barriers, indicating that the dissociation of N 2 is facile under mild conditions. The reaction process can be divided into two processes: N 2 transfer (TRF) and NÀ N dissociation (DIS). For V-series clusters, which has a V atom on Site 1, the rate-determining step is DIS, while for Ta-series clusters with a Ta on Site 1, TRF may be the rate-determining step or has energy barriers similar to those of DIS. The overall energy barriers for heteronuclear V 2 TaC 4 À and VTa 2 C 4 À clusters are lower than those for homonuclear V 3 C 4 À and Ta 3 C 4 À , showing that the doping effect is beneficial for the activation and dissociation of N 2 . In particular, VÀ Ta 2 C 4 À has low energy barriers in both TRF and DIS, and it has the highest N 2 adsorption energy and a high reaction heat release. Therefore, a trimetallic heteronuclear V-series cluster, VÀ Ta 2 C 4 À , is suggested to have high reactivity to N 2 activation, and may serve as a prototype for designing related catalysts at a molecular level.

ZrN6‐Doped Graphene for Ammonia Synthesis: A Density Functional Theory Study

“…Due to the strong intermolecular N�N triple bonds, only diazotrophs or lightning could transfer the stable molecule into ammonia in nature. [4] Currently, the ammonia is produced massively by the energy-intensive Haber-Bosch process, leading to heavy energy consumption and carbon emission. [5][6][7][8][9] As a promising green technology, the nitrogen electro-reduction toward ammonia via consecutive protonation could be achieved at room temperature.…”

Exploring trimetallic clusters containing alkali and alkaline earth metal atoms with high activity for nitrogen activation

“…On bimetallic clusters, N 2 can rst obtain the adsorption intermediate of side-on:end-on and then dissociate [35,37], or it can pass through the intermediate of side-on:side-on and then dissociate [40][41][42]. On trimetallic clusters, N 2 is adsorbed on the center of the metal triangle in the form of end-on:side-on:side-on or end-on:end-on:side-on coordination modes before dissociation [43][44][45][46].…”

Exploring Trimetallic Clusters Containing Alkali and Alkaline Earth Metal Atoms with High Activity for Nitrogen Activation

“…On bimetallic clusters, N 2 can rst obtain the adsorption intermediate of side-on:end-on and then dissociate [35,37], or it can pass through the intermediate of side-on:side-on and then dissociate [40][41][42]. On trimetallic clusters, N 2 is adsorbed on the center of the metal triangle in the form of end-on:side-on:side-on or end-on:end-on:side-on coordination modes before dissociation [43][44][45][46].…”