High-performance N2-to-NH3 fixation by a metal-free electrocatalyst

Abstract

The Haber–Bosch process for the synthesis of ammonia (NH₃) not only causes large energy consumption but also leads to CO₂ emissions. Electrocatalytic hydrogenation of N₂ to NH₃ under ambient conditions is a highly desirable alternative method; however, it needs an efficient electrocatalyst. In this study, we report a mesoporous boron nitride (MBN) metal-free electrocatalyst for the N₂ reduction reaction under ambient conditions. Owing to its mesoporous structure, this MBN electrocatalyst can expose more active sites, resulting in an outstanding NH₃ formation rate of 18.2 μg h⁻¹ mg_cat.⁻¹ with a faradaic efficiency of 5.5% at −0.7 V vs. reversible hydrogen electrode in 0.1 M Na₂SO₄. It also demonstrates strong long-term electrochemical durability.