Palladium metallene for nitric oxide electroreduction to ammonia

Area of Science:

• Electrochemistry
• Catalysis
• Materials Science

Background:

• Electrocatalytic reduction of nitric oxide (NO) to ammonia (NH3) is a crucial process for nitrogen management and sustainable ammonia production.
• Developing efficient and selective catalysts for NO reduction in neutral media remains a significant challenge.

Purpose of the Study:

• To investigate the potential of palladium (Pd) metallene as a catalyst for the electrocatalytic reduction of NO to NH3 (NORR).
• To determine the catalytic performance, including faradaic efficiency and yield rate, under neutral conditions.

Main Methods:

• Electrochemical experiments were conducted to evaluate the NORR performance of Pd metallene.
• Density Functional Theory (DFT) calculations were employed to understand the reaction mechanism and active sites.

Main Results:

• Pd metallene demonstrated high catalytic activity for NORR, achieving a maximum NO-to-NH3 faradaic efficiency of 89.6%.
• An ammonia (NH3) yield rate of 112.5 μmol h-1 cm-2 was recorded at -0.3 V in neutral media.
• Theoretical calculations revealed that the hexagonal close-packed (hcp) site of Pd facilitates effective NO activation and hydrogenation via a low-energy pathway.

Conclusions:

• Pd metallene is a highly efficient catalyst for the electrocatalytic reduction of NO to NH3 in neutral electrolytes.
• The study elucidates the catalytic mechanism, highlighting the role of the hcp site in Pd for efficient NO hydrogenation.
• This work presents a promising advancement in electrocatalytic ammonia synthesis using non-precious metal catalysts.