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.