Metal Catalysts for Selective Hydrogenation of Small Unsaturated Hydrocarbons: What Controls Catalytic Performance?

Selective hydrogenation of small hydrocarbons, exemplified by acetylene and 1,3-butadiene, under mild conditions is not only industrially critical but also serves as a benchmark for catalyst development. Designing effective supported metal catalysts for these reactions requires more than just high activity; it demands excellent selectivity to avoid over-hydrogenation and polymer formation, along with long-term stability under reaction conditions. While substantial progress has been made in developing selective hydrogenation catalysts, a systematic review that dissects the key factors affecting catalytic performance remains lacking. This review fills that gap by critically analyzing the roles of several fundamental parameters, including the geometric structure of supported metal species, support characteristics, the presence of secondary metal components, and the effects of controlled poisoning and coating of the active centers. By isolating and evaluating the impact of each factor, this review aims to provide clear insights that support the rational design of high-performance supported metal catalysts for selective hydrogenation. These insights are intended to guide future research toward more efficient, stable, and selective catalytic systems.