Pd−Zn Alloy Nanoparticles Encapsulated into Mesoporous Silica with Confinement Effect for Highly Selective Semi‐Hydrogenation of Phenylacetylene

Abstract

AbstractIn the process of hydrogenation of phenylacetylene to styrene, it is a crucial step to improve the reaction selectivity of the target product styrene. Herein, we have designed the Pd−Zn alloy nanoparticles encapsulated into mesoporous silica with confinement effect (Pd−Zn@MS) for highly selective semi‐hydrogenation of phenylacetylene via annealing the Pd NPs@ZIF‐8 in reducing atmosphere. The as‐obtained Pd−Zn@MS achieved up to the 95 % of conversion rate and 92 % of selectivity, because the mesoporous silica exhibits a steric hindrance effect for the reactant molecular size, and the Pd−Zn alloy nanoparticles shows the high selectivity for the target product styrene. DFT calculations demonstrates that the PdZn alloy nanoparticles can reduce significantly the desorption energy barrier of styrene from 1.72 eV to 0.95 eV, compared with the Pd nanoparticles. Meanwhile the mesoporous silica in the outer layer greatly guarantees the stability of the catalytic performance of the catalyst, and the catalytic performance did not drop after the five‐cycle test. This work provides a new idea for the selective hydrogenation of phenylacetylene and the process of limited‐area catalysis.