Recent advances in thermocatalytic acetylene selective hydrogenation

Selective acetylene hydrogenation is a crucial reaction for purifying ethylene in the petroleum industry and presents a promising non-oil route for producing ethylene by integrating acetylene production from natural gas and coal. Despite significant advancements in catalyst development, achieving both high catalytic activity and ethylene selectivity remains challenging due to competing side reactions, including over-hydrogenation to ethane, C-C coupling leading to oligomers, and C-C bond cleavage resulting in coke formation. This review provides a comprehensive overview of recent progress in the development of catalysts and understanding of reaction mechanism for acetylene hydrogenation to ethylene. Firstly, benchmarks for conversion and selectivity calculation are critically discussed. Then, research on active site design is categorized into monometallic sites, disordered alloy sites, intermetallic compound (IMC) sites, and single-atom (SA) sites, with a distinction between Pd-based and non-Pd-based catalysts. This categorization highlights the active site design strategies and summarizes state-of-the-art performance metrics. Emphasis is placed on the structure-performance relationships and the role of different active metals in enhancing ethylene selectivity and catalytic activity. In addition, the roles of catalyst support and modifiers are reviewed. Finally, we discuss challenges and future research directions in mechanistic understanding and catalyst design, aiming to guide further innovations in this important field.