Frontiers in Acetylene Semi‐Hydrogenation: Advanced Catalyst Engineering and Mechanistic Unraveling for Ethylene Production

ABSTRACT Ethylene, a key petrochemical feedstock, is typically produced via steam cracking. To obtain polymer‐grade ethylene, acetylene semihydrogenation is employed to remove trace acetylene impurities from the raw ethylene stream. The prevailing industrial method relies on conventional thermal catalysis, which operates under harsh conditions such as elevated temperature and pressure conditions, presenting significant economic and environmental challenges. Enhancing the conversion efficiency and economic viability of this reaction is therefore of critical importance. This review comprehensively summarizes recent advances in the semihydrogenation of acetylene to ethylene, with a focus on catalyst design and reaction mechanisms across three major routes: thermal catalysis, electrocatalysis, and photocatalysis. It further examines the roles of bimetallic systems, single‐atom catalysts, and advanced support materials. Finally, key challenges are outlined to guide the development of more economical, green, and sustainable pathways.