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

• Published in: Journal of materials chemistry. A, Materials for energy and sustainability Vol. 1; no. 15; pp. 8245 - 8251
• Main Authors: Huang, Peng, Cheng, Zhuo, Zeng, Liang, Tan, Lulu, Yu, Jian, Rushikesh, Joshi, Fan, Liang-Shih, Zhu, Yujie
• Format: Journal Article
• Language: English
• Published: Cambridge Royal Society of Chemistry 12.04.2022
• Subjects: Adsorption; Ammonia; Bismuth; Chemical reduction; Density functional theory; Electrical conductivity; Electrical resistivity; Electrochemistry; Graphene; Hydrogen; Hydrogen evolution reactions; Sulfuric acid
• ISSN: 2050-7488; 2050-7496
• DOI: 10.1039/d2ta00673a

Bismuth (Bi) has triggered rising scientific inquiry in the field of the electrochemical N 2 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 N 2 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 N 2 adsorption, enhanced exposure of Bi active sites, and favorable inhibition of the hydrogen evolution reaction, odBi-hRGO showed a stimulative average NH 3 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 H 2 SO 4 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. A composite consisting of oxide-derived Bi embedded in the holes of reduced graphene oxide is synthesized for N 2 electroreduction. The synergistic effect between the Bi defects and graphene vacancies leads to a high NH 3 activity and selectivity.