Density Functional Theory Study of Nitrogen Reduction to Ammonia on Bilayer Borophene

The N2 reduction reaction (NRR) under ambient conditions is highly desirable because of its potential to replace the energy-consuming Haber-Bosch process for ammonia production. In recent years, much attention has been devoted to transition metal-based catalysts. However, the development of metal-free electrocatalysts remains a great challenge. Here, the electrocatalytic performance of bilayer borophene is systematically studied based on first-principles calculations. It was found that bilayer borophene has high activity with an overpotential of 0.21 V via the enzymatic mechanism. Bond elongations of nitrogen bond are observed in end-on and side-on patterns, where the bond lengths are stretched to 1.13 and 1.21 Å, respectively. Around 0.36 e− is transferred to the adsorbed N2 with the contribution of bottom boron atoms. Our results propose bilayer borophene as a novel metal-free catalyst for nitrogen reduction, thus providing an avenue to explore highly efficient electrocatalysts for ammonia production under ambient conditions.