Hydrodesulfurization catalysts for ultra-clean diesel: Recent progress, modulation strategies, and emerging alternatives

Abstract

The tightening of global environmental regulations and the growing emphasis on carbon neutrality have driven the petroleum industry to pursue ultra-clean fuels. Diesel, as a dominant transportation fuel, faces particularly stringent sulfur limits due to the adverse environmental and operational impacts of sulfur oxides. Hydrodesulfurization (HDS) remains the most mature and efficient industrial technology for producing low-sulfur diesel; however, the escalating demands for ultra-deep desulfurization and low-carbon operation have placed unprecedented challenges on catalyst performance. Despite significant advances in catalyst formulation, systematic reviews dedicated specifically to HDS catalyst development remain scarce. This review provides a comprehensive overview of recent progress in HDS catalysis, emphasizing strategies for modulating active phases, supports, and novel unsupported catalysts. The fundamental mechanisms governing desulfurization pathways are briefly summarized to establish the theoretical foundation for subsequent discussions. Recent advances in tuning metal–support interactions, tailoring acidity, and employing heteroatom or promoter modifications to enhance catalytic activity are critically analyzed. Support regulation strategies—including compositional modification of γ-Al₂O₃ and zeolite-based systems—are examined with attention to structure–performance correlations and industrial applicability. The review further explores the emerging class of unsupported catalysts, highlighting template-assisted synthesis and three-dimensional framework designs as promising directions. Finally, key scientific challenges and future prospects are outlined, aiming to provide guidance for the rational design of next-generation HDS catalysts that enable sustainable production of ultra-clean diesel.