NOx Electrochemical Oxidation
Featured Publication:
Picture shows DFT analysis of the reaction mechanism. a) Possible reaction mechanisms for electrochemical NO oxidation to HNO3. b) Optimized structures of four oxygen functional groups on graphene edge sites. c) Free-energy diagrams of electrochemical NO oxidation on hydroxy edge structures at an applied potential of 0 V, comparing the NO2* and HNO2* pathways.
Key Findings
- First electrochemical route for direct conversion of nitric oxide (NO) into concentrated, salt-free nitric acid under near-ambient conditions.
- Mechanistic discovery of HNO3 as the key reaction intermediate, challenging the conventional oxidation pathway.
- DFT-guided reaction mechanism revealing the elementary oxidation steps and their thermodynamic origins.
- Carbon-based catalyst design enabling high activity, selectivity, and stability.
- Achieved >90% Faradaic efficiency for nitric acid production from pure NO at industrially relevant current densities.
- Showcased the power of combining first-principles simulations and experiments to accelerate catalyst discovery and electrochemical process development.
Sustainable Production of High-Purity Nitric Acid from Nitric Oxide Emissions
Nitric oxide (NO) is a major atmospheric pollutant generated from industrial processes, transportation, and energy production. Instead of treating NO solely as a waste product, our research demonstrates a sustainable electrochemical strategy that converts NO directly into high-purity nitric acid (HNO3) under near-ambient conditions using earth-abundant carbon-based catalysts. This approach transforms an environmental liability into a valuable industrial chemical while eliminating the need for harsh operating conditions and energy-intensive thermochemical processes.
Using DFT calculations together with experimental validation, we uncovered the atomic-scale reaction mechanism governing NO electrooxidation. Our computational studies identified HNO2 as the key reaction intermediate, revealing a reaction pathway fundamentally different from the conventional Ostwald process. These mechanistic insights guided catalyst design and enabled the development of an electrochemical system capable of producing salt-free, concentrated nitric acid with exceptional efficiency.
By integrating mechanistic modeling with electrochemical engineering, this work establishes a new platform for sustainable nitrogen chemistry, demonstrating how computational catalysis can accelerate the development of clean technologies for pollution mitigation and green chemical manufacturing.