Modulating CoFe2O4 nanocube with oxygen vacancy and carbon wrapper towards enhanced electrocatalytic nitrogen reduction to ammonia

• Published in: Applied catalysis. B, Environmental Environmental, 2021-11, Vol.297, p.120452, Article 120452
• Main Authors: Wang, Chuang, Gu, Liang-Liang, Qiu, Sheng-You, Gao, Jian, Zhang, Yong-Chao, Wang, Ke-Xin, Zou, Ji-Jun, Zuo, Peng-Jian, Zhu, Xiao-Dong
• Format: Article
• Language: English
• Subjects: Ammonia; Bimetals; Carbon; Catalytic activity; Chemical reduction; Cobalt ferrites; CoFe2O4; Electrocatalyst; Electrolysis; Electronic structure; Nitrogen; Nitrogen reduction reaction; Oxygen; Oxygen vacancy; Pigments; Prussian blue analogue; Sodium sulfate; Transition metals; Vacancies
• ISSN: 0926-3373; 1873-3883
• DOI: 10.1016/j.apcatb.2021.120452

A hollow bimetallic CoFe2O4 nanocube rationally modulated by carbon wrapper and oxygen vacancy demonstrates an overwhelming synergetic effect, achieving superior activity, stability and durability towards electrochemical nitrogen reduction reaction under ambient conditions. [Display omitted] •Hollow C@CoFe2O4-x nanocube is devised and proposed as novel NRR electrocatalyst.•PBA-derived CoFe2O4 nanocube demonstrates great intrinsic activity.•Carbon wrapper and oxygen vacancy are introduced via facile strategies.•Prominent synergy effect ensures superior activity, selectivity and durability. Electrocatalytic nitrogen reduction reaction is increasingly deemed as a promising route for massive ammonia synthesis. Herein, hollow bimetallic CoFe2O4 nanocube derived from prussian blue analogue is elaborately wrapped by thin carbon layer and modified by rich oxygen vacancies, achieving splendid ammonia yield rate of 30.97 μg h−1 mgcat.−1 and Faradaic efficiency of 11.65 % at −0.4 V versus reversible hydrogen electrode in 0.1 M Na2SO4. In addition, C@CoFe2O4-x nanocube can withstand long-term and repetitive electrolysis without obvious structure collapse, constituent change and activity decay. The prominent activity is strongly associated with improved nitrogen adsorption and activation, collaboratively benefiting from the intrinsic unoccupied d orbitals of transition metal components, reformative electronic structure by oxygen vacancies and elevated electron injection possibility into the antibonding orbital of nitrogen molecule via conductive carbon wrapper. Both actual experiments and theoretical investigations attest the catalytic activity improvement mechanism, rendering the C@CoFe2O4-x nanocube design strategy efficient and valid.