Photocatalytic Methods for Nitric Oxide Removal

Photocatalytic removal of nitric oxide (NO) represents a promising route to mitigate urban and industrial air pollution by harnessing solar or artificial light to drive oxidation and reduction pathways. Semiconductor materials absorb photons to generate electron–hole pairs, which in turn produce reactive oxygen species capable of converting NO into less harmful nitrogen oxides, nitrates or molecular nitrogen. Innovations in materials design—such as heterostructure engineering, surface functionalisation and plasmonic enhancement—have sought to overcome limitations in light harvesting, charge separation and selectivity, particularly the undesirable accumulation of toxic NO2 intermediates. Recent advances span metal–organic frameworks, two-dimensional and bionic architectures, polymeric carbon nitrides and metal-decorated oxides, all tailored to operate efficiently at parts-per-billion pollutant concentrations. Scaling up to continuous-flow reactors and pilot systems has further demonstrated the practical potential of these photocatalytic technologies for real-world air purification.

Research from Nature Portfolio

A pioneering study introduced a biomimetic photocatalyst that emulates chloroplast architecture by embedding carbon nanotubes within discontinuous semiconductor networks. Localised microwave heating generates super-hot spots, inducing rapid assembly of titanium-oxide domains along the nanotube scaffold. This three-dimensional “chloroplast-structured” system exhibits dual electron transfer pathways, achieving record photocatalytic NO removal efficiency of around 86 % under ultraviolet irradiation. The intimate carbon–semiconductor interface enhances charge separation, while the high surface area and tailored morphology enable exceptional conversion rates, pointing towards broadly applicable design principles for high-performance environmental photocatalysts.

Photocatalytic Methods for Nitric Oxide Removal publication trend

The graph below shows the total number of articles in photocatalytic methods for nitric oxide removal across all publications each year (not limited to Nature Index journals).

Technical terms

Photocatalysis: Light-driven acceleration of redox reactions on the surface of a semiconductor.

Heterojunction: Interface between two semiconductors with differing band structures, enhancing charge separation.

Surface Plasmon Resonance (SPR): Collective oscillation of conduction electrons in metal nanoparticles under light irradiation, amplifying local electromagnetic fields.

Reactive Oxygen Species (ROS): Highly reactive radicals such as superoxide (·O2−) and hydroxyl (·OH) that oxidise pollutants.

Band Gap: Energy difference between the valence and conduction bands in a semiconductor, determining its light-absorption threshold.

References

1. A chloroplast structured photocatalyst enabled by microwave synthesis. Nature Communications (2019).
2. Unlocking photocatalytic NO removal potential in an S‐type UiO‐66‐NH2/ZnS(en)0.5 heterostructure. Interdisciplinary Materials (2024).
3. Cyano/Hydroxyl Groups Co-Functionalized g-C3N4 for Photocatalytic NO Removal: A Synergistic Strategy towards Inhibition of Toxic Intermediate NO2. Catalysts (2023).
4. Plasmonic Bi-Modified Bi2Sn2O7 Nanosheets for Efficient Photocatalytic NO Removal. Catalysts (2024).