Recent Advances in Catalysts and Reaction Mechanism for the Direct Conversion of Ethanol to Butadiene

Butadiene is a key monomer in the production of synthetic rubber, resins, and fine chemicals. Although significant progress has been made in the technology for the direct conversion of ethanol to butadiene (ETB), challenges remain in the development of highly efficient catalysts and the elucidation of the structure–activity relationships of supported catalysts. Furthermore, there are few systematic reviews analyzing the structure–activity relationships in the direct ETB conversion. In this review, we summarize recent advances in catalysts for direct ETB conversion and systematically analyze the relationships among metal composition, preparation method, support structure, active-site environment, and catalytic performance, and the competitive C–C coupling mechanism, reaction kinetics, catalyst deactivation, and regeneration strategies. Furthermore, we present the technical bottlenecks and future opportunities in the direct ETB conversion. This review aims to comprehensively analyze the structure–activity relationships between catalysts and catalytic performance in the direct ETB conversion, with the goal of promoting the development of efficient catalysts and accelerating the industrialization of ETB conversion.