MnO2 nanoarray with oxygen vacancies: An efficient catalyst for NO electroreduction to NH3 at ambient conditions

Electrochemical NO reduction into NH3 addresses the need for harmful NO abatement and offers an attractive alternative to the industrial Haber–Bosch process, but it requires the development of advanced catalysts with high activity and selectivity toward NH3 synthesis. In this work, we report on our recent experimental findings that a MnO2 with oxygen vacancies (VO) nanowire array on Ti mesh (MnO2-x NA/TM) behaves as a high-active and stable electrocatalyst for ambient NO reduction to NH3. In 0.2 M Na2SO4, such catalyst shows a large NH3 yield of 27.51 × 10−10 mol s−1 cm−2 and a high Faradic efficiency of 82.8%, considerably outperforming the pristine MnO2 counterpart (8.83 × 10−10 mol s−1 cm−2, 44.8%). Density function theory calculations indicate that NO adsorption is enhanced on MnO2-x (211) surface due to stronger electronic interaction between NO and Mn atoms as a result of the VO.