Related Experiment Video
Updated: Mar 3, 2026
09:50
Electrochemically and Bioelectrochemically Induced Ammonium Recovery
Published on: January 22, 2015
13.3K
Self-Sustaining Dynamic Alkaline Microenvironment-Mediated Efficient Nitrate Electroreduction to Ammonia on MnFeOx in
Xinmei Jia1, Yan Kong1, Da Wan2
1Department of Chemical Physics, University of Science and Technology of China, Hefei, Anhui, People's Republic of China.
Angewandte Chemie (International Ed. in English)
|March 2, 2026
Summary
This study introduces a MnFe dual-site oxide catalyst that creates a self-sustaining alkaline microenvironment for efficient electrocatalytic nitrate reduction (NO3RR) in neutral water, boosting ammonia synthesis.
Area of Science:
- Electrochemistry
- Materials Science
- Environmental Chemistry
Background:
- Electrocatalytic nitrate reduction (NO3RR) offers sustainable ammonia synthesis but faces challenges in neutral media due to slow kinetics and hydrogen evolution reaction (HER) competition.
- Developing efficient electrocatalysts for NO3RR in neutral conditions is crucial for wastewater treatment and green ammonia production.
Purpose of the Study:
- To develop a novel catalyst for efficient electrocatalytic nitrate reduction (NO3RR) in neutral media.
- To investigate a
- self-sustaining alkaline local microenvironment
- strategy to enhance NO3RR performance and suppress HER.
Main Methods:
- Synthesized a 1D MnFe dual-site oxide catalyst (MnFeO x) by selectively substituting Fe sites with Mn.
- Utilized in-situ characterization to understand the formation and role of the localized alkaline microenvironment at the electrode-electrolyte interface.
- Performed electrochemical measurements to evaluate NO3RR performance, including Faradaic efficiency and current density.
Main Results:
- The 1D MnFeO x catalyst successfully established a self-sustaining alkaline microenvironment, suppressing HER and promoting NO3RR.
- Achieved a high NH3 Faradaic efficiency of 95.9% (12.3 mg h-1 cm-2) in neutral media.
- Demonstrated excellent stability, operating for over 20 hours without degradation.
Conclusions:
- The MnFe dual-site oxide catalyst effectively regulates the local interfacial microenvironment for enhanced NO3RR.
- This work provides a new strategy for adaptive electrocatalyst design by enabling intelligent self-regulation of local pH.
- The findings offer significant insights for advancing sustainable ammonia synthesis and wastewater treatment technologies.
Related Concept Videos
01:15Metabolism of Chemolithotrophs
1.0K
Chemolithotrophs are microorganisms that obtain energy by oxidizing inorganic molecules such as hydrogen gas (H₂), ammonia (NH₃), reduced sulfur compounds (H₂S, S²⁻), and ferrous iron (Fe²⁺). Unlike heterotrophic organisms that rely on organic carbon, chemolithotrophs transfer electrons from these inorganic donors to the electron transport chain (ETC), generating a proton motive force (PMF) that drives ATP synthesis through oxidative phosphorylation.
1.0K
01:28Microbial Nutrition
1.7K
Organisms exhibit remarkable metabolic diversity, categorized based on how they acquire energy and carbon. These strategies enable survival in various ecological niches and are essential for maintaining energy flow and nutrient cycling within ecosystems.Energy and Carbon SourcesOrganisms are classified as phototrophs or chemotrophs based on energy acquisition. Phototrophs use light as their energy source, while chemotrophs rely on oxidizing chemical compounds. Further differentiation arises...
1.7K
01:22Inorganic Nitrogen Assimilation
680
Nitrogen is an essential element in biological systems, forming a crucial component of proteins, nucleic acids, and other cellular constituents. Many bacteria and archaea acquire nitrogen in the form of nitrate (NO₃⁻) or ammonia (NH₃), which are then assimilated into biomolecules through specific enzymatic pathways.Assimilatory Nitrate ReductionWhen nitrate enters the cell, it undergoes a two-step reduction process known as assimilatory nitrate reduction. Initially, the enzyme...
680
01:24Electrochemical Systems
19
Electrochemical systems provide a fascinating insight into the dynamic interplay of charged species within various phases. One notable example is the interaction between a membrane permeable to K⁺ ions but not to Cl⁻ ions, separating an aqueous KCl solution from pure water. As K⁺ ions diffuse through the membrane, they generate net charges on each phase, leading to a potential difference between them.Similarly, when a piece of Zn is immersed in an aqueous ZnSO₄ solution,...
19
01:20Titration of a Weak Base with a Strong Acid
9.3K
The titration curve of a weak base like ammonia with a strong acid like hydrochloric acid is the mirror image of the titration curve of a weak acid with a strong base.
Using the ICE table and substituting the Kb value, we calculate the initial pH of 50 mL of 0.1 M ammonia to be 11.11. Addition of 25 mL of 0.1 M hydrochloric acid to this solution of ammonia results in a buffer with an equal concentration of ammonia and ammonium ions. The pH of this buffer can be calculated by substituting these...
Using the ICE table and substituting the Kb value, we calculate the initial pH of 50 mL of 0.1 M ammonia to be 11.11. Addition of 25 mL of 0.1 M hydrochloric acid to this solution of ammonia results in a buffer with an equal concentration of ammonia and ammonium ions. The pH of this buffer can be calculated by substituting these...
9.3K
01:30Ladder Diagrams: Redox Equilibria
829
Ladder diagrams are useful tools for understanding redox equilibrium reactions, especially the effects of concentration changes on the electrochemical potential of the reaction. The vertical axis in the redox ladder diagrams represents the electrochemical potential, E. The area of predominance is demarcated using the Nernst equation.
Consider the Fe3+/Fe2+ half-reaction, which has a standard-state potential of +0.771 V. At potentials more positive than +0.771 V, Fe3+ predominates, whereas Fe2+...
Consider the Fe3+/Fe2+ half-reaction, which has a standard-state potential of +0.771 V. At potentials more positive than +0.771 V, Fe3+ predominates, whereas Fe2+...
829