Molecule Saturation Boosts Acetylene Semihydrogenation Activity and Selectivity on a Core‐Shell Ruthenium@Palladium Catalyst

Abstract

Increasing selectivity without the expense of activity is desired but challenging in heterogeneous catalysis. By revealing the molecule saturation and adsorption sensitivity on overlayer thickness, strain, and coordination of Pd-based catalysts from first-principles calculations, we designed a stable Pd monolayer (ML) catalyst on a Ru terrace to boost both activity and selectivity of acetylene semihydrogenation. The least saturated molecule is most sensitive to the change in catalyst electronic and geometric properties. By simultaneously compressing the Pd ML and exposing the high coordination sites, the adsorption of more saturated ethylene is considerably weakened to facilitate the desorption for high selectivity. The even stronger weakening to the least saturated acetylene drives its hydrogenation such that it is more exothermic, thereby boosting the activity. Tailoring the molecule saturation and its sensitivity to structure and composition provides a tool for rational design of efficient catalysts.

Construction of Enriched Metal Vacancies to Enhance Catalytic Behavior for Selective Hydrogenation Over Au–Cu Nanoalloys

“…5 This could be realized commercially over supported Pd-based catalysts, but they suffer from poor selectivity. 6,7 Gold as a latent green catalyst has been found to be selective for the hydrogenation of some unsaturated groups, such as C�O and C�C, owing to its unique nature to desorb olefins at lower temperatures than alkynes. 8,9 In the past few decades, much effort has been devoted to the development of novel Au catalysts, including the modification of Au particle size, the introduction of second metals, or the selection of the suitable supports.…”

“…About 75% of ethylene is obtained by naphtha cracking along with the generation of acetylene impurities that would irreversibly poison polymerization catalysts. , Consequently, the modern polyolefin industry demands the acetylene concentration in the ethylene feed to be less than 1 ppm. , Considering the atomic economy, selective acetylene hydrogenation to ethylene is regarded as the most state-of-the-art route for ethylene purification . This could be realized commercially over supported Pd-based catalysts, but they suffer from poor selectivity. , …”

Structure Sensitivity of Metal Catalysts Revealed by Interpretable Machine Learning and First-Principles Calculations

“…Catalysis plays a pivotal role in a wide range of chemical processes, enabling the synthesis of vital materials and the conversion of raw resources into value-added products. , In the quest for sustainable and environmentally friendly chemical transformations, the development of efficient catalysts that selectively activate target molecules is of utmost importance. − Supported transition metals (TMs) are widely used to improve the catalytic activity and selectivity for their great tunability of geometry structure, − composition, , size, − and strong metal–support interaction − among others. Talyor proposed nearly one century ago that unsaturated active sites control the reactivity, and Boudart classified the catalytic reactions as either structure sensitive or insensitive .…”

Metal–Organic Framework-Derived Ni–S/C Catalysts for Selective Alkyne Hydrogenation

“…Selective catalytic hydrogenation of acetylene impurities in an ethylene-rich stream is an important industrial process in the production of polyethylene feedstock. , With the increasingly urgent societal requirement for green chemical processes, more stringent requirements have been put forward for producing polymer-grade ethylene in which the acetylene content must be reduced to <1 ppm. , Consequently, the efficient hydrogenation of acetylene to ethylene has become a key challenge in catalysis. Pd-based catalysts are considered the most active materials at present and are thus widely used for this reaction industrially under mild reaction conditions .…”