Enhanced selective hydrogenation of acetophenone over KIT-6 supported Pd–MOx (M = Fe, Co, Ni) hybrid nanostructures

Abstract

Modifying noble metal catalysts with transition metal oxides (MO_x) can markedly enhance catalytic performance through synergistic effects, yet precise spatial colocalization of active metal and promoter phases remains challenging. Here, we report the synthesis of KIT-6 supported Pd–MO_x (M = Fe, Co, Ni) hybrid nanostructures via in situ transformation of bimetallic PdM nanoparticles under controlled thermal conditions. The resulting Pd–MO_x/KIT-6 catalysts displayed superior activity and selectivity in the selective hydrogenation of acetophenone to 1-phenylethanol compared with monometallic Pd/KIT-6. Among them, Pd–CoO_x/KIT-6 (Pd/Co = 1 : 1) achieved the highest performance, with 99.7% acetophenone conversion and 98.2% selectivity, and demonstrated broad applicability for hydrogenating diverse ketones. Structural and kinetic studies revealed that interfacial Pd–CoO_x sites play a pivotal role: Pd domains efficiently dissociate H₂, while CoO_x species enhance acetophenone adsorption. This synergistic interface-driven mechanism provides a general and cost-effective strategy for the selective hydrogenation of multifunctional substrates.