[en] Pd-P nanoparticles were obtained by low-temperature reduction of Pd(acac)₂ with hydrogen in the presence of elemental phosphorus. Using the EDX analysis, XRD, and HRTEM, the composition, size, and morphology of the particles were determined for different P:Pd ratios. The results of testing Pd-P nanoparticles showed that they are 8–9 times higher in activity in the hydrogenation of mono- and di-substituted acetylenic compounds than Pd-black and phase-pure Pd₃P phosphide, while maintaining high selectivity to alkenes at 95–98% conversion of alkynes. Colloidal solutions of Pd-P nanoparticles can act as long-lived supported catalysts (TON = 27,444 mol PA·(mol Pd _total)⁻¹). The effect of the P:Pd ratio on the change in the rates of hydrogenation of alkyne (r₁) and the resulting alkene (r₂) under the action of Pd-P nanoparticles has been found and experimentally substantiated. Electron-deficient small clusters of palladium contained along with palladium phosphides in the Pd-P nanoparticles are responsible for the decrease in the ratio r₁:r₂ in the ratio range P:Pd = 1–1.5.

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