Enhancing electrochemical nitrogen fixation by mimicking π back-donation on laser-tuned Lewis acid sites in noble-metal-molybdenum carbide

Conventional electrocatalysts underperform with reaction kinetics, nitrogen dissociation, and activated hydrogen recombination, demanding effective strategies for improving electrochemical nitrogen fixation. The challenge lies in the rational design of electron back-donating centers for nitrogen activation and hydrogen migration path optimization. This study proposes an effective laser-tuning strategy to construct noble-metal Lewis acid sites on molybdenum carbide (M-Mo2C, M = Ru, Rh, Pd, Ir), yielding a more active material system by mimicking π back-donation behavior. Laser-tuned Lewis acid sites can effectively break N≡N bonds, lower thermodynamic energy barrier of the rate-determining hydrogenation step (*NN → *N-NH), and optimize hydrogen migration pathway. The Rh-Mo2C shows superior NRR activity with NH3 yield of ∼26.3 µg h−1 cm−2cat. and Faradaic efficiency of ∼15.4%, which are 5.1- and 3.6-fold higher than those of Mo2C, respectively. This work demonstrates a unique and universal strategy for designing high-performance electrocatalysts by accurately manipulating electronic structure of active sites.