Bismuth-Based Free-Standing Electrodes for Ambient-Condition Ammonia Production in Neutral Media

Electrocatalytic nitrogen reduction reaction is a carbon-free and energy-saving strategy for efficient synthesis of ammonia under ambient conditions. Here, we report the synthesis of nanosized Bi₂O₃ particles grown on functionalized exfoliated graphene (Bi₂O₃/FEG) via a facile electrochemical deposition method. The obtained free-standing Bi₂O₃/FEG achieves a high Faradaic efficiency of 11.2% and a large NH₃ yield of 4.21 ± 0.14 [Formula: see text] h^-1 cm^-2 at - 0.5 V versus reversible hydrogen electrode in 0.1 M Na₂SO₄, better than that in the strong acidic and basic media. Benefiting from its strong interaction of Bi 6p band with the N 2p orbitals, binder-free characteristic, and facile electron transfer, Bi₂O₃/FEG achieves superior catalytic performance and excellent long-term stability as compared with most of the previous reported catalysts. This study is significant to design low-cost, high-efficient Bi-based electrocatalysts for electrochemical ammonia synthesis.