SnNb2O6 nanosheets for the electrocatalytic NRR: dual-active-center mechanism of Nb3c and Sn4c–Nb5c dimer

The electrochemical nitrogen reduction reaction (NRR) provides a promising route for energy-effective and sustainable ammonia synthesis, while developing high-efficiency NRR electrocatalysts is extremely desirable. Here we first exploited foordite SnNb2O6 nanosheets as an effective and durable NRR catalyst, which presented an NH3 yield of 53.1 μg h−1 mg−1 and a faradaic efficiency of 17.6% at −0.3 V (vs. reversible hydrogen electrode). Theoretical computations uncovered the dual-active-center mechanism of Nb3c (3c means three-fold coordinated bond) and Sn4c–Nb5c dimer on SnNb2O6 (311) to synergistically enhance the N2 adsorption and activation, consequently lowering the energy barrier for the rate-determining step and boosting the electrocatalytic NRR.