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 Nb3 , Zr3 , and Y3 , 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 N2 adsorption and NN* activation performances of Nb3 , Zr3 , and Y3 . Our findings demonstrate that the medium and low positive fields promote the N2 adsorption performance of Nb3 , while both positive and negative fields enhance nitrogen adsorption on Zr3 . Additionally, electric fields may impede N2 fixation on Y3 , yet the N2 adsorption performance of Y3 remains considerable. Negative electric fields enhance the NN* activation performance of Nb3 and Y3 . But only high negative fields weaken the NN bond on Zr3 , which is attributed to the promotion of the charge accumulation around two N atoms. Notably, Nb3 and Zr3 are identified as two TATMCs with the potential for simultaneous optimization of their EN and ICOHP values. This work sheds light on the field effects on the N2 adsorption and NN* activation performances of TATMCs and guides the design of catalysts for achieving more sustainable ammonia synthesis.