Boosting Electrocatalytic Nitrogen Reduction on Cobalt‐Based Perovskite via Regulating Reaction Pathway Through Donation‐Back‐Donation Modulation

Abstract

Abstract The electrocatalytic approach of combining N 2 and H 2 O to produce ammonia, known as the electrocatalytic N 2 reduction reaction (eNRR), has garnered significant attention due to its environmental benefits and potential for supporting a decentralized agricultural economy. However, the underlying chemistry governing the reaction pathways remains poorly understood, hindering the design of low‐cost and efficient eNRR catalysts. Here we report the enhancement of the electrocatalytic eNRR activity of perovskite oxides by tuning the reaction pathway through a “donation‐back‐donation” mechanism. This is achieved by controlling the spin state via adjusting the distribution of d orbital electrons in low‐cost transition metals, such as cobalt. Specifically, the cobalt in perovskite SrCoO 3 (SC) with a low‐spin state demonstrates an 18 times higher ammonia yield rate compared to that in Co 3 O 4 and 1.5 times higher than cobalt in perovskite LaCoO 3 (LC). The low spin states of cobalt in SC enable better control of the eNRR reaction pathway over the transformation of *N 2 H to *NHNH or *NNH 2 , resulting in alternating hydrogenation in SC rather than distal hydrogenation in LC with a high spin state. The unprecedented improvement in eNRR by regulating the spin state of Co demonstrates the bright of low‐cost Co‐based electrocatalysts for ammonia production.