Hydrogen peroxide-assisted oxidative desulfurization: mechanisms and catalytic perspectives

The growing environmental concerns and stricter global fuel regulations on sulfur content have accelerated the search for efficient desulfurization technologies. Oxidative Desulfurization (ODS) has emerged as a promising complement or alternative to conventional Hydrodesulfurization (HDS), offering advantages such as mild operating conditions, reduced energy consumption, and superior performance in removing refractory sulfur compounds. Among various oxidants, hydrogen peroxide (H₂O₂) has attracted significant interest due to its environmental compatibility, cost-effectiveness, and the benign nature of its by-products-water and oxygen. This review emphasizes mechanistic insights into H₂O₂-based ODS, focusing on the activation of H₂O₂ and subsequent oxidation of sulfur species. Catalytic systems such as organic acids, polyoxometalates (POMs), ionic liquids (ILs), deep eutectic solvents (DESs), transition metal oxides, and metal-organic frameworks (MOFs) have been widely explored for enhancing H₂O₂ activation. The generation of reactive oxygen species (ROS), especially hydroxyl radicals (•OH), plays a pivotal role in oxidizing organic sulfur compounds into polar sulfoxides and sulfones, enabling their easy separation. Recent progress in catalyst design has yielded highly efficient and reusable systems under mild conditions, underscoring the potential of H₂O₂-assisted ODS as a sustainable pathway for producing ultra-low sulfur fuels.