Construction of Ln₂O₃@C Nanosheets for Electrocatalytic Nitrogen Reduction to Ammonia

Lanthanide metal possesses multiple oxide states, which endows it with potential advantages as promising catalysts for electrochemical ammonia synthesis. A universal method was developed to prepare Ln₂O₃@C (Ln = La, Er, Tb, and Eu) nanosheets via calcinating Ln-citrate nanosheets under a N₂ atmosphere. Ln-citrate nanosheets were obtained via a cation change method. The carbon from the carbonization of citrate not only supported the generated lanthanide oxide but also inhibited the aggregation of nanoparticles during the high-temperature calcination. La₂O₃@C nanosheets displayed a high charger transfer ability, considerable chemical active surface, and N₂ adsorption ability. La₂O₃@C nanosheets exhibited outstanding electrocatalytic nitrogen reduction reaction performance, with an NH₃ production rate of 20.59 μg h^-1 mg^-1 and faradaic efficiency of 17.10%. Meanwhile, Eu₂O₃@C, Tb₂O₃@C, and Er₂O₃@C nanosheets were also synthesized with excellent electrocatalytic performance. This study provided a method for fabricating metal oxide nanosheets for pronounced electrochemical nitrogen fixation.