Assistant Professor Jason Lam from the School of Energy and Environment (SEE) at City University of Hong Kong (CityUHK) has recently published a research paper in Angewandte Chemie International Edition, titled "In-tandem Electrochemical Reduction of Nitrate to Ammonia on Ultrathin-Sheet-Assembled Iron–Nickel Alloy Nanoflowers". Dr. Kartick Chandra Majhi, a postdoctoral fellow in Prof. Lam's group, served as the first author, while Prof. Lam was the corresponding author. Theoretical calculations were conducted with support from Prof. Patrick Sit, also from the SEE at CityUHK.

The development of alternative ammonia (NH?) synthesis pathways with high Faradaic efficiency (FE) is crucial for reducing energy consumption and achieving carbon neutrality. Electrocatalytic nitrate reduction to NH? (e–NO?RRA) presents a promising alternative to the energy-intensive, fossil-fuel-driven Haber–Bosch process. In this study, Prof. Lam and his team successfully synthesized an ultra-stable iron–nickel nanoflower alloy through a one-pot electrodeposition protocol. This alloy was utilized for e–NO?RRA under alkaline conditions, achieving a remarkable Faradaic efficiency of 97.28 ± 1.36% at -238 mV vs. the reversible hydrogen electrode (RHE).

The team elucidated an electrochemical nitrate reduction mechanism involving an in-tandem process using the Fe??Ni?? alloy catalyst. Specifically, during the electroreduction of NO??, nitrate ions are adsorbed and activated on the iron surface within the sheet-assembled nanoflower, while nickel accelerates water dissociation to enhance hydrogen coverage on the alloy surface. This hydrogen spillover facilitates the migration of adsorbed hydrogen to NO??, thereby promoting its conversion to NH?.

The article was designated as a "Hot Paper" in the field of nitrate reduction research by an editor and featured on the outside back cover of the journal. At CityUHK, Prof. Lam focuses his research on electrocatalysis to transform renewable feedstocks and waste materials into chemicals and fuels. His research encompasses the electrocatalytic upgrading of biomass, the treatment of wastewater pollutants using advanced oxidation processes, and the electrochemical extraction of metals from electronic waste.

Open-Access Article URL: https://onlinelibrary.wiley.com/doi/full/10.1002/anie.202500167
Outside Back Cover URL: https://onlinelibrary.wiley.com/doi/10.1002/anie.202505571