A simple descriptor for the nitrogen reduction reaction over single atom catalysts.

The performance of supported catalysts is largely decided by metal-support interactions, which is of great significance for the rational design of catalysts. However, how to quantify the structure-activity relationship of supported catalysts remains a great challenge. In this work, taking MoS 2 and WS 2 supported single atom catalysts (SACs) as prototypes, a simple descriptor, namely, effective d electron number (labeled as Φ ), is constructed to quantitatively describe the effect of metal-support interaction on the nitrogen reduction reaction (NRR) activity. This descriptor merely consists of intrinsic properties of the catalyst (including the number of d electrons, electronegativity of the metal atoms and generalized electronegativity of the substrate atoms) and can accurately predict the limiting potential ( U L ) for the NRR, with no need for any density functional theory calculations. Moreover, this descriptor possesses superb expansibility that can be applied to other materials, including other metal dichalcogenide (MoSe 2 , MoTe 2 , WSe 2 , WTe 2 and NbS 2 ) and even MXene (V 2 CO 2 , Ti 2 CO 2 and Nb 2 CO 2 )-supported SACs. On this basis, a fast screening of excellent NRR catalysts among these systems is performed and three promising NRR catalysts ( i.e. Mo@WTe 2 , Mo@V 2 CO 2 and Re@NbS 2 ) are successfully selected with U L as low as -0.32, -0.24 and -0.31 V, respectively. This work offers new opportunities for advancing the rapid discovery of high-efficiency NRR catalysts, and the design principle is expected to be widely applicable to other catalytic systems and beyond.