V₂O₃/VN electrocatalysts with coherent heterogeneous interfaces for selecting low‐energy nitrogen reduction pathways

Abstract

Abstract Electrochemical nitrogen reduction reaction (NRR) is a sustainable alternative to the Haber‒Bosch process for ammonia (NH 3 ) production. However, the significant uphill energy in the multistep NRR pathway is a bottleneck for favorable serial reactions. To overcome this challenge, we designed a vanadium oxide/nitride (V 2 O 3 /VN) hybrid electrocatalyst in which V 2 O 3 and VN coexist coherently at the heterogeneous interface. Since single‐phase V 2 O 3 and VN exhibit different surface catalytic kinetics for NRR, the V 2 O 3 /VN hybrid electrocatalyst can provide alternating reaction pathways, selecting a lower energy pathway for each material in the serial NRR pathway. As a result, the ammonia yield of the V 2 O 3 /VN hybrid electrocatalyst was 219.6 µg h −1 cm −2 , and the Faradaic efficiency was 18.9%, which is much higher than that of single‐phase VN, V 2 O 3 , and VN x O y solid solution catalysts without heterointerfaces. Density functional theory calculations confirmed that the composition of these hybrid electrocatalysts allows NRR to proceed from a multistep reduction reaction to a low‐energy reaction pathway through the migration and adsorption of intermediate species. Therefore, the design of metal oxide/nitride hybrids with coherent heterointerfaces provides a novel strategy for synthesizing highly efficient electrochemical catalysts that induce steps favorable for the efficient low‐energy progression of NRR.