From metal nodes to sulfur capture: design principles and challenges in MOF-based adsorptive desulfurization

The persistent presence of thiophenic sulfur compounds in fuels is a major challenge for achieving ultra-deep desulfurization because conventional methods struggle to remove stable aromatic molecules like DBT, BT, and 4,6-DMDBT. Their strong molecular rigidity, low reactivity, and steric hindrance limit the effectiveness of existing technologies, underscoring the urgent need for advanced materials capable of selectively capturing these recalcitrant sulfur species. Metal-organic frameworks (MOFs) have emerged as promising materials for deep desulfurization, but selectively removing thiophenic sulfur compounds is still difficult because these molecules are highly stable and interact weakly with conventional adsorbents. This review tackles this issue by examining MOFs designed with π-rich linkers, mixed-valent metal centers, and unsaturated metal sites that improve sulfur capture through stronger π-π interactions, π-complexation, and metal-sulfur coordination. Unlike general surveys, this work uniquely integrates mechanistic insights, structure-property correlations, computational analysis, and real-fuel performance to establish clear design principles for high-efficiency adsorption. By critically comparing top-performing frameworks and highlighting advances in post-synthetic modification and composite development, the review outlines how rational structural tuning can overcome the limitations of traditional adsorbents. This unified perspective offers a strategic roadmap for guiding future research toward sustainable, high-performance MOF-based desulfurization technologies.