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

Highlights The Bi 2 O 3 nanoplates homogeneously decorated free-standing exfoliated graphene (Bi 2 O 3 /FEG) was prepared by a facile electrochemical deposition method. The Bi 2 O 3 /FEG first used as nitrogen reduction electrocatalyst exhibits excellent electrocatalysis performance and stability for nitrogen reduction reaction in neutral media. The superior electrocatalytic nitrogen reduction activity is attributed to the strong interaction of the Bi 6 p band with the N 2 p orbitals, binder-free nature of the electrodes, and facile electron transfer through the graphene nanosheets. 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 Bi 2 O 3 particles grown on functionalized exfoliated graphene (Bi 2 O 3 /FEG) via a facile electrochemical deposition method. The obtained free-standing Bi 2 O 3 /FEG achieves a high Faradaic efficiency of 11.2% and a large NH 3 yield of 4.21 ± 0.14 μ g NH 3 h −1 cm −2 at − 0.5 V versus reversible hydrogen electrode in 0.1 M Na 2 SO 4 , better than that in the strong acidic and basic media. Benefiting from its strong interaction of Bi 6 p band with the N 2 p orbitals, binder-free characteristic, and facile electron transfer, Bi 2 O 3 /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.