Pulsed Electrocatalysis Enabling High Overall Nitrogen Fixation Performance for Atomically Dispersed Fe on TiO2

Atomically dispersed Fe was designed on TiO2 and explored as a Janus electrocatalyst for both nitrogen oxidation reaction (NOR) and nitrogen reduction reaction (NRR) in a two-electrode system. Pulsed electrochemical catalysis (PE) was firstly involved to inhibit the competitive hydrogen evolution reaction (HER) and oxygen evolution reaction (OER). Excitingly, an unanticipated yield of 7055.81 mu mol h(-1) g(cat.)(-1) and 12 868.33 mu mol h(-1) g(cat.)(-1) were obtained for NOR and NRR at 3.5 V, respectively, 44.94 times and 7.8 times increase in FE than the conventional constant voltage electrocatalytic method. Experiments and density functional theory (DFT) calculations revealed that the single-atom Fe could stabilize the oxygen vacancy, lower the energy barrier for the vital rupture of N equivalent to N, and result in enhanced N-2 fixation performance. More importantly, PE could effectively enhance the N-2 supply by reducing competitive O-2 and H-2 agglomeration, inhibit the electrocatalytic by-product formation for longstanding *OOH and *H intermediates, and promote the non-electrocatalytic process of N-2 activation.