Facile N≡N Bond Cleavage by Anionic Trimetallic Clusters V<sub>3−<i>x</i></sub>Ta<sub><i>x</i></sub>C<sub>4</sub><sup>−</sup> (<i>x=</i>0–3): A DFT Study
Ya‐Ya Wang, Xunlei Ding, Joseph Israel Gurti, Yan Chen, Xue‐Qian Huang, Wei Li, Xin Wang
Abstract
Abstract Activation of N 2 on anionic trimetallic V 3− x Ta x C 4 − ( 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 N−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 − and VTa 2 C 4 − clusters are lower than those for homonuclear V 3 C 4 − and Ta 3 C 4 − , showing that the doping effect is beneficial for the activation and dissociation of N 2 . In particular, V−Ta 2 C 4 − 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, V−Ta 2 C 4 − , is suggested to have high reactivity to N 2 activation, and may serve as a prototype for designing related catalysts at a molecular level.