Impact of Oxygen-Containing Groups on Pd/C in the Catalytic Hydrogenation of Acetophenone and Phenylacetylene

Pd/C catalysts play a pivotal role in contemporary chemical industries due to their exceptional performance in diverse hydrogenation processes and organic reactions. Over the past century, researchers have extensively explored the factors influencing Pd/C catalyst performance, particularly emphasizing the impact of oxygen-containing groups through oxidation or reduction modifications. However, most studies use respective Pd/C catalysts to analyze the catalytic reactions of one or a class of chemical bonds (polar or non-polar). This study investigates alterations in Pd/C catalysts during temperature-programmed reduction (TPR) and evaluates the hydrogenation activity of unsaturated polar bonds (C=O, acetophenone) and non-polar bonds (C≡C, phenylacetylene) in Pd/C catalysts. The experimental results indicate that the reduction of Pd/C decreases the content of oxygen-containing groups, reducing hydrogenation activity for acetophenone but increasing it for phenylacetylene. This research highlights the preference of regular Pd surfaces for non-polar bond reactions and the role of Pd/oxide sites in facilitating polar bond hydrogenation. These discoveries offer essential insights into how oxygen-containing groups influence catalytic performance and allow us to propose potential avenues for enhancing the design and production of Pd/C catalysis.