Adjustment of the Single Atom/Nanoparticle Ratio in Pd/CNT Catalysts for Phenylacetylene Selective Hydrogenation

Abstract Pd/C catalysts are widely used for hydrogenation reactions in the chemical industry. One of the reasons for their high activity is the ability of Pd nanoparticles (Pd NP ) to dissociate H 2 and promote H‐spillover. Nevertheless, for selective hydrogenation unpromoted Pd/C catalysts show disappointing results. The use of supported Pd single atom (Pd SA ) catalysts permits to achieve high selectivity. However, Pd SA show low activity because they have difficulty in activating H 2 . A cooperative catalysis between Pd NP and Pd SA operates for the hydrogenation of alkenes thanks to the H‐spillover, which makes it possible to obtain active isolated Pd SA −H species. Here, we present experimental and computational results obtained for phenylacetylene hydrogenation on Pd/CNT catalysts showing different Pd SA /Pd NP ratios. Tuning this ratio allows doubling the activity while reaching high selectivity to styrene at high conversion. DFT calculations suggest that the first coordination sphere of Pd SA has a pronounced effect on their reactivity.