Rational design of Mo2C nanosheets anchored on hierarchically porous carbon for boosting electrocatalytic N2 reduction to NH3

Electrocatalytic nitrogen reduction reaction (NRR) is promising for achieving ammonia (NH3) synthesis under ambient conditions, but restricted by the lack of efficient catalysts. Herein, 3D hierarchical architectures of Mo2C nanosheets supported on porous carbon matrix (Mo2[email protected]) are rationally designed for boosting the electrocatalytic NRR. The morphology engineering endows Mo2[email protected] electrocatalysts with hierarchically porous architectures, which can sufficiently expose the surface-active sites and enhance the mass diffusion and electron transfer. Moreover, the composition modulation strategy can not only retain the adequate adsorption of N2, but also restrict the hydrogen evolution reaction (HER). Accordingly, Mo2[email protected] electrocatalysts exhibit a high NH3 yield rate of 12.55 ± 1.04 μg/h/mg at −0.20 V vs. RHE and a well-balanced Faradaic efficiency. Theoretical calculations further confirm the strong N2 adsorption/activation on the Mo2C catalyst and the NRR mechanism of the preferred distal pathway. The morphology engineering and composition modulation strategies can be extended to other materials, guiding the rational design of efficient NRR catalysts.