Using photocatalysis for sustainable agriculture: R-leaf's potential in large-scale N2O mitigation

Addressing climate change through the removal of greenhouse gases (GHGs) is crucial for achieving global environmental goals. Nitrous oxide (N₂O) has gained increasing attention due to its significant global warming potential—approximately 300 times that of CO₂—and its rising atmospheric levels, largely driven by intensive agriculture. Among the various methods proposed for air pollutant removal, photocatalysis presents a promising and sustainable approach, especially if utilising solar light as an excitation source. This work investigates the photocatalytic removal of N₂O using R-Leaf, a TiO₂-based photocatalyst, under both controlled laboratory conditions and real-world field applications. In laboratory experiments conducted in a batch photoreactor R-Leaf achieved N₂O conversion rates between 6 % and 12 %, depending on initial concentrations and atmospheric conditions. Notably, in air, conversion efficiency increased, indicating a promising role for oxygen in enhancing photocatalytic activity. Finally, to demonstrate the potential of R-Leaf for applications in large agricultural areas, a small-scale field trial was performed. After application of the photocatalyst, approximately 1 ppbv of N₂O was removed when compared with a nearby control field without the R-Leaf. While the observed change in N₂O concentration was relatively small, its impact is magnified by the vast scale of global agricultural land. These findings highlight R-Leaf's potential as a sustainable solution for decarbonizing agriculture, paving the way for large-scale photocatalytic air purification.