Background: At present, industrial synthesis of NH3 mainly relies on the Haber-Bosch
process, which is characterized by harsh reaction conditions and high energy consumption. Electrochemical
nitrogen reduction is considered to be a mild and sustainable alternative method for producing
NH3, but efficient electrocatalyst under ambient conditions is the prerequisite for NH3 production.
Objective: To demonstrate that CP@MnO2 ultralong nanowires are a highly-efficient electrocatalyst
for N2 reduction reaction (NRR) under ambient conditions.
Methods: The α-phase MnO2 synthesized by one-step hydrothermal method has an ultralong nanowires
structure and oxygen vacancy defects. The catalysts were characterized by XRD, TEM, XPS,
etc. The produced NH3 was estimated by indophenol blue method by UV-vis absorption spectra.
Results: Such catalyst attains high Faradaic efficiency (FE) of 8.8% and a large NH3 yield of
1.13×10−10 mol cm−2 s−1 at −0.7 V versus reversible hydrogen electrode in 0.1 M Na2SO4. In addition,
the catalyst also shows high electrochemical stability and selectivity for NH3 formation.
Conclusion: MnO2 ultralong nanowires can expose higher density of active sites and the spontaneously
formed oxygen vacancies can manipulate the electronic structure of manganese oxides and provide
coordination unsaturation sites (CUS) to enhance the adsorption of N2, which is the main reason for
the high activity of the catalyst.