In Situ Derived Co<sub>2</sub>B Nanosheet Array: A High-Efficiency Electrocatalyst for Ambient Ammonia Synthesis via Nitrate Reduction
Lisi Xie, Shengjun Sun, Long Hu, Jie Chen, Jun Li, Ling Ouyang, Yongsong Luo, Abdulmohsen Ali Alshehri, Qingquan Kong, Qian Liu, Xuping Sun
Abstract
Ambient ammonia synthesis via electrochemical nitrate (NO3–) reduction is regarded as a green alternative to the Haber–Bosch process. Herein, we report the in situ derivation of an amorphous Co2B layer on a Co3O4 nanosheet array on a Ti mesh (Co2B@Co3O4/TM) for efficient NH3 production via selective electroreduction of NO3– under ambient conditions. In 0.1 M PBS and 0.1 M NaNO3, Co2B@Co3O4/TM exhibits a maximum Faradaic efficiency of 97.0% at −0.70 V and a remarkable NH3 yield of 8.57 mg/h/cm2 at −1.0 V, with durability for stable NO3–-to-NH3 conversion over eight recycling tests and 12 h of electrolysis. Additionally, it can be applied as an efficient cathode material for Zn-NO3– batteries to produce NH3 while generating electricity. The catalytic mechanisms on Co2B@Co3O4 are further revealed by theoretical calculations.