Efficient photocatalytic oxidation of nitrogen containing compounds of fuel over heterojunctions under visible light irradiation: photocatalysts classification, process parameters, kinetics, and mechanisms

Nitrogen containing compounds (NCCs) in fuel can impact fuel processing, consistency of catalyst, and safety of fuel transportation. Currently, oxidation of NCCs is critical due to increasingly stringent environmental regulations. There are different processes for NCCs removal, such as biodenitrogenation (BDN), oxidative denitrogenation (ODN), extractive denitrogenation (EDN), hydrodenitrogenation (HDN), adsorptive denitrogenation (ADN), and photocatalytic oxidation of NCCs. Photocatalytic oxidation of NCCs has emerged as an appealing, eco-friendly technology for the refining of fuel oil. It typically involves the photocatalytic breakdown of refractory NCCs into simpler, more polar nitrogen species (e.g., NO 3 - , NH 4 + ), which are subsequently removed from the fuel phase via extraction into a polar solvent or adsorption, achieving true removal. The current review discusses the benefits and drawbacks of photocatalytic oxidation of NCCs photocatalysts, as well as the features that make certain photocatalysts highly effective. There are several types of photocatalysts in the oxidation of NCCs of fuels, containing bismuth, titanium, zinc, and metal-organic frameworks (MOFs) based photocatalysts. In particular, key strategies for enhancing performance including photocatalyst selection, modification, and other essential photocatalytic oxidation of NCCs parameters are analyzed to derive a mechanistic framework for an effective photocatalytic oxidation of NCCs process. The study on photocatalytic oxidation of NCCs has been developed by the promotion of technology and the refining of fuels. This research investigates different types of photocatalysts, process parameters, kinetics, mechanisms, and future outlooks in photocatalytic oxidation of NCCs.