Electrocatalytic Nitrogen Reduction to Ammonia

The electrocatalytic reduction of nitrogen to ammonia offers a sustainable alternative to the energy-intensive Haber–Bosch process by operating under ambient conditions and utilising renewable electricity. Molecular nitrogen, with its strong triple bond, presents a kinetic barrier that demands catalysts capable of activating N₂ and steering successive proton–electron transfers towards NH₃ formation while suppressing the competing hydrogen evolution reaction. Progress in this field centres on the design of high-surface-area materials, single-atom and tandem catalysts, and the fine-tuning of electrolytes to enhance adsorption of nitrogen species, lower overpotential requirements and improve Faradaic efficiency. Beyond direct N₂ reduction, electrocatalytic conversion of nitrate contaminants into ammonia has emerged as a complementary route that combines pollutant remediation with value-added chemical synthesis. The integration of advanced catalyst architectures with mechanistic insights and in-situ characterisation is paving the way for decentralised ammonia production, on-site fertiliser generation and energy storage applications, thereby addressing both agricultural demand and decarbonisation goals.

Research from Nature Portfolio

Researchers have demonstrated a bifunctional CuCo nanosheet catalyst that mimics the active centres of nitrite reductase, achieving near-quantitative Faradaic efficiencies for NO₃⁻-to-NH₃ conversion at ampere-level current densities. Synergistic interaction between Cu sites, which facilitate nitrate adsorption, and Co sites, which promote hydrogenation via adsorbed hydrogen species, enables a high ammonia yield rate and energy efficiency. In another advance, a core–shell tandem catalyst derived from Cu–Co binary sulfides has been shown to orchestrate cascade reduction of NO₃⁻ to NH₃ with Faradaic efficiencies exceeding 90% over a broad concentration range. The inner Cu/CuOx phase preferentially reduces NO₃⁻ to NO₂⁻, while the adjacent Co/CoO shell completes the multi-electron conversion to ammonia, thus overcoming scaling relations and enhancing reaction kinetics under mild conditions.

Electrocatalytic Nitrogen Reduction to Ammonia publication trend

The graph below shows the total number of articles in electrocatalytic nitrogen reduction to ammonia across all publications each year (not limited to Nature Index journals).

Technical terms

Faradaic efficiency: The fraction of total electric charge that contributes to the desired chemical reaction rather than side reactions.

Overpotential: The additional potential beyond the thermodynamic requirement needed to drive an electrochemical reaction at a desired rate.

Hydrogen evolution reaction (HER): The electrochemical generation of hydrogen gas, which competes with nitrogen reduction at cathodic potentials.

Single-atom catalyst: A catalyst in which individual metal atoms are dispersed on a support, maximising atomic utilisation and providing well-defined active sites.

Triple bond activation: The process by which the strong N≡N bond in molecular nitrogen is weakened or cleaved to enable subsequent hydrogenation steps.

References

1. Ampere-level current density ammonia electrochemical synthesis using CuCo nanosheets simulating nitrite reductase bifunctional nature. Nature Communications (2022).
2. Splicing the active phases of copper/cobalt-based catalysts achieves high-rate tandem electroreduction of nitrate to ammonia. Nature Communications (2022).
3. Pathways of the Electrochemical Nitrogen Reduction Reaction: From Ammonia Synthesis to Metal-N2 Batteries. Electrochemical Energy Reviews (2023).
4. Identification of Dynamic Active Sites Among Cu Species Derived from MOFs@CuPc for Electrocatalytic Nitrate Reduction Reaction to Ammonia. Nano-Micro Letters (2023).