Electrochemical Ammonia Oxidation via Junctional Catalysis
1 October 2026
Affiliation
NUS
Focus topic
Low-carbon H2 & Derivatives
-
Summary
This technology introduces a heterogeneous-homogeneous junctional electrocatalysis (Hetero-homo-JE) approach for electrochemical ammonia oxidation, enabling the selective conversion of ammonia into high-value nitrite and nitrate — key feedstocks for fertilizers, pharmaceuticals, and the food industry — as an alternative to the energy-intensive Ostwald process.
Key quantitative achievements:
Activity: 400 mA cm⁻² at 1.5 V vs. RHE (Ni foam); further enhanced to 1,400 mA cm⁻² at 1.5 V vs. RHE with an optimised Ni-based electrode
Selectivity: ~80% nitrite faradaic efficiency maintained across a broad current density range (10–1,400 mA cm⁻²)
Stability: 200 hours of continuous operation at 200 mA cm⁻² in a membrane electrode assembly (MEA) reactor
Energy efficiency: Significantly reduced cell voltage compared to conventional oxygen evolution reaction (OER)-based systems
Scalability: Demonstrated in a MEA reactor configuration; electrode preparation uses a simple, room-temperature, solution-based process
Product yield: ~0.6 M NOₓ⁻ accumulated in electrolyte during MEA operation
What makes this novel compared to best-in-class technology?
Unlike conventional solid-phase Ni-Cu alloy catalysts, this strategy employs dissolved Cu²⁺ ions as a homogeneous redox mediator working synergistically with a Ni-based heterogeneous electrode. This uniquely eliminates catalyst poisoning, decouples electron and proton transfer, and maintains ~80% nitrite selectivity at current densities up to 40× higher than leading reported catalysts.
TRL Level
1-3
Relevant for
Green hydrogen producers using ammonia as a hydrogen carrier (ammonia fuel cells / electrochemical ammonia cracking)
Ammonia fuel cell developers requiring efficient anode oxidation catalysts
Specialty chemical producers supplying nitrite/nitrate for pharmaceutical and food-grade applications
Electrolyser / stack manufacturers integrating MEA-based ammonia oxidation systems
Green ammonia project developers and energy storage operators using ammonia as an energy vector.
Fertilizer manufacturers seeking lower-energy nitrite/nitrate production routes to replace the Ostwald process.
About
Inventors: Chen Wei
Affiliation: National University of Singapore (NUS), Department of Chemistry
Contact NUS for licensing opportunities and more information.
Please quote ID ref [2023-420] in your email.