Tuning nitrogen adsorption and activation performances of Three-Atom transition metal clusters by modulating external electric fields.

Three-atom transition metal clusters (TATMCs) with remarkable catalytic activities, especially Nb, Zr, and Y, are proven to be suitable candidates for efficient ammonia production. The pursuit of effective strategies to further promote the ammonia synthesis performance of TATMCs is necessary. In this study, we systematically investigate the effect of external electric fields on tuning the N adsorption and NN* activation performances of Nb, Zr, and Y. Our findings demonstrate that the medium and low positive fields promote the N adsorption performance of Nb, while both positive and negative fields enhance nitrogen adsorption on Zr. Additionally, electric fields may impede N fixation on Y, yet the N adsorption performance of Y remains considerable. Negative electric fields enhance the NN* activation performance of Nb and Y. But only high negative fields weaken the NN bond on Zr, which is attributed to the promotion of the charge accumulation around two N atoms. Notably, Nb and Zr are identified as two TATMCs with the potential for simultaneous optimization of their E and ICOHP values. This work sheds light on the field effects on the N adsorption and NN* activation performances of TATMCs and guides the design of catalysts for achieving more sustainable ammonia synthesis.