Promoting the formation of oxygen vacancies in ceria multishelled hollow microspheres by doping iron for enhanced ambient ammonia electrosynthesis

Abstract

The electrochemical nitrogen reduction reaction (NRR) is an environmentally friendly and sustainable approach for NH₃ synthesis at mild pressure and temperature, but the implementation depends on efficient electrocatalysts. Herein, iron-doped ceria multishelled hollow microspheres are explored as an efficient and robust electrocatalyst for the NRR in 0.1 M Na₂SO₄, achieving a high NH₃ yield of 34.79 μg h⁻¹mg_cat⁻¹ with a considerable faradaic efficiency of 36.66% at −0.4 V versus reversible hydrogen electrode (RHE), surpassing the pure ceria catalyst. Doping iron induces the formation of rich oxygen vacancies in ceria, which facilitates the capture of nitrogen molecules and accelerates the cleavage of NN bonds, thereby enhancing the catalytic performance.