Phenylcarbazole-stabilized palladium catalysts for efficient acetylene hydrochlorination†

9-Phenylcarbazole (PCz) was employed to synthesize Pd-based/SAC catalysts using an ultrasonic-assisted impregnation method for acetylene hydrochlorination. The catalytic performance of the Pd–PCz/SAC catalysts was investigated, and the Pd–15PCz/SAC catalyst achieved 99.9% C₂H₂ conversion and over 99% vinyl chloride monomer (VCM) selectivity, with negligible catalyst deactivation over 380 h. Characterization demonstrated that the addition of PCz effectively stabilized the active Pd(ii) particles, inhibited carbon deposition, and prevented the loss of active Pd species. Density functional theory (DFT) simulations further verified the positive effect of PCz modification on the Pd-based/SAC catalyst by altering the energy profiles of reaction pathways and the adsorption energies of reactants and products, thus enhancing catalytic efficiency.