Steering intrinsic activity in electrochemical nitrogen reduction reaction by coupling catalytic resonance theory and breaking scaling relation

Electrochemical nitrogen reduction reaction (NRR) is a promising route for sustainable ammonia synthesis, yet its practical implementation is hindered by sluggish kinetics and competing hydrogen evolution reaction (HER). There is a consensus that increasing the intrinsic activity of NRR catalysts can help overcome the selectivity problem with respect to the HER. Enhancing the intrinsic activity can be achieved by two different approaches: on the one hand, the breaking of linear free energy relationships between reaction intermediates in the catalytic cycle. On the other hand, the concept of catalytic resonance theory modifies the free-energy diagram through a dynamic ratchet mechanism and thus changes the linear free energy relationships between reaction intermediates. In the present study, we combine breaking scaling relation and catalytic resonance theory to uncover their effects on the intrinsic activity of NRR catalysts by referring to the class of materials of transition-metal oxides. By applying a data-driven method using a potential-dependent activity descriptor, G max ( U ), three-dimensional volcano plots are constructed to determine optimal catalytic conditions for ammonia synthesis. Our study provides guidelines for the rational design of NRR catalysts with enhanced intrinsic activity.