Holey reduced graphene oxide-assisted oxide-derived Bi for efficient nitrogen electroreduction

Abstract

Bismuth (Bi) has triggered rising scientific inquiry in the field of the electrochemical N₂ reduction reaction (NRR) due to its weak hydrogen binding capability and superior hydrogenation ability of *NN to *NNH. However, the application extension of Bi has been restricted owing to its unfavorable adsorption and activation of N₂ and its poor electrical conductivity. Reconstructing Bi itself or combining it with other materials is a universal strategy to address these challenges. Here, by integrating these two strategies, we report a simple thermal method to directly synthesize oxide-derived Bi anchored in holey reduced graphene oxide (odBi-hRGO). Benefiting from the unique structure which exhibits elevated N₂ adsorption, enhanced exposure of Bi active sites, and favorable inhibition of the hydrogen evolution reaction, odBi-hRGO showed a stimulative average NH₃ yield and faradaic efficiency of up to 8.89 μg cm⁻² h⁻¹ at −0.6 V (versus the reversible hydrogen electrode) and 24.34% at −0.55 V in 0.05 M H₂SO₄ under ambient conditions. Density functional theory calculations further reveal that oxide-derived Bi with under-coordinated sites is more favorable for the NRR than ideal Bi while hRGO plays a critical role in suppressing the hydrogen evolution reaction.