Reaction of Nitrate Radicals and DMPO in Non-Aqueous Media: A Novel Detection Tool to Highlight the Nitrate Radical Role in Photocatalytic Processes

The reaction of DMPO as the spin trapping agent with nitrate radicals photocatalytically generated results in the formation of DMPOX showing a highly specific EPR spectrum. The method can be used as a semi-quantitative and convenient way to detect nitrate radicals in non-aqueous solutions/suspensions, which was never achieved up to now through EPR spectroscopy. Results support in a more direct way the proposed generation and reactivity of nitrate radicals in photocatalytic media and open a new chapter in the field of heterogeneous photocatalysis.