Efficient Electro-Catalytic Desulfurization by In-Situ Oxidant Generation

In this study, we present an extraction-coupled electro-catalytic oxidative desulfurization (EC-EODS) system that achieves efficient sulfur removal from fuel oils without external oxidants. The system utilizes an electrolyte composed of ionic liquids (ILs), NaCl, and H₂SO₄, integrating extraction and electrochemical oxidation to effectively remove different aromatic sulfur compounds with sulfur removals of 100%. Additionally, H₂ is co-produced at the cathode, supporting refinery processes and reducing H₂ storage and transportation costs, thereby improving economic viability. Detailed mechanism analysis shows that IL selectively extracts and concentrates sulfur compounds, while NaCl and H₂SO₄ facilitate ClO^- generation, serving as the in-situ oxidant. The EC-EODS system operates without external catalysts, relying on graphite electrodes that generate superoxide radicals from ClO^-. Moreover, a strategy for the separation of desulfurization products as well as the electrolyte is proposed as well. The EC-EODS system offers a sustainable, high-efficiency strategy for desulfurization, with economic benefits through sulfur oxidation and H₂ co-generation.