Electrochemical N2 fixation to NH3 under ambient conditions: porous LiFe5O8 nanoparticle–reduced graphene oxide as a highly efficient and selective catalyst

Abstract

Traditional NH₃ production based on the Haber–Bosch process is usually accompanied by high energy consumption and a large amount of carbon dioxide emission, which are not conducive to the realization of global carbon neutralization. Electrochemical N₂ reduction is regarded as a clean strategy to deal with this problem. In this work, porous LiFe₅O₈ nanoparticle–reduced graphene oxide (rGO) is proposed as an efficient electrocatalyst for artificial N₂-to-NH₃ fixation with excellent selectivity under ambient conditions. Electrochemical tests in 0.1 M HCl show that such a hybrid achieves a high NH₃ yield of 36.025 mg h⁻¹ mg_cat.⁻¹ and a high faradaic efficiency of 13.08% at −0.2 V vs. the reversible hydrogen electrode. Furthermore, it also exhibits structural stability. Theoretical calculations reveal that LiFe₅O₈–rGO can efficiently catalyze NH₃ synthesis with a low energy barrier.