A review on catalyst deactivation in the oxidative desulfurization process: Causes and mitigation strategies

In recent years, oxidative desulfurization (ODS) has gained significant attention as a promising solution for removing sulfur compounds from fuel oils, particularly heavy marine fuels, to comply with increasingly stringent environmental regulations. While most ODS studies focus on developing catalysts for high activity, deactivation is a frequent and significant challenge in this process. Yet relatively few studies specifically address this issue. This review provides a comprehensive overview of the causes of catalyst deactivation reported in the literature, with a focus on their occurrence with respect to the reaction conditions. Key factors such as sulfone deposition, active phase leaching, deposition of non-sulfur compounds, and the impact of water presence are discussed. Additionally, mitigation strategies are listed and categorized into three approaches: catalyst regeneration approaches, catalyst design modifications, and reaction conditions optimization. By providing this information, the review aims to establish an understanding to guide the development of robust catalysts capable of maintaining high performance even in complex feed matrices.