Catalytic Reduction Mechanisms in Gas-Phase Pollutants

Catalytic reduction mechanisms in gas-phase pollutants centre on the transformation of harmful species such as nitrogen oxides (NOx) and carbon monoxide into innocuous molecules, primarily molecular nitrogen (N₂) and carbon dioxide (CO₂). Heterogeneous catalysts—ranging from supported noble metals to transition-metal oxides—provide active sites where reactant gases adsorb and undergo sequential redox cycles. Key factors governing activity and selectivity include the creation and migration of oxygen vacancies, strong metal–support interactions and the design of dual-site architectures. Advances in operando spectroscopy and computational modelling have deepened understanding of elementary steps, enabling the tailoring of surface electronic states to lower activation barriers and enhance tolerance to inhibitors such as H₂O and SO₂. Applications span automotive exhaust after-treatment, industrial flue-gas cleaning and indoor air purification. Emerging strategies involve single-atom catalysts, alloy and cluster systems, and spinel oxides, which together offer routes to lower operating temperatures, improved stability and the use of earth-abundant materials, thereby addressing the global imperative for cleaner air.

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Catalytic Reduction Mechanisms in Gas-Phase Pollutants publication trend

The graph below shows the total number of articles in catalytic reduction mechanisms in gas-phase pollutants across all publications each year (not limited to Nature Index journals).

Technical terms

Selective Catalytic Reduction (SCR): A process in which a reductant (e.g. CO, NH₃ or H₂) converts NOx to N₂ and H₂O or CO₂ over a catalyst.

NOx: Collective term for nitrogen oxides, chiefly nitric oxide (NO) and nitrogen dioxide (NO₂), produced by combustion processes.

Single-atom catalyst: A catalyst in which isolated metal atoms are dispersed on a support, maximising atomic efficiency and unique electronic properties.

Oxygen vacancy: A defect in an oxide lattice where an oxygen atom is missing, facilitating redox reactions by enhancing oxygen mobility.

Spinel structure: A crystal lattice of the form AB₂O₄, often employed in mixed-metal oxides for robust redox performance.

Redox cycle: Alternating reduction and oxidation steps in a catalytic mechanism that regenerate the active state of the catalyst.

References

1. Synergistic Catalysis of Rh Single‐Atom and Clusters Supported on TiO2 Nanosheet Array for Highly Efficient Removal of CO and NOx. Small Structures (2024).
2. Low-Temperature Selective NO Reduction by CO over Copper-Manganese Oxide Spinels. Catalysts (2022).
3. Recent Advances of Cu-Based Catalysts for NO Reduction by CO under O2-Containing Conditions. Catalysts (2022).