Active Sites Engineering through Palladium-Phosphorus Synergy for Heterogeneously-Catalyzed Alkoxycarbonylation Reactions

Crystalline palladium phosphide (Pd3P) nanoparticles on silica were investigated for the alkoxycarbonylation of aryl halides, providing a strategic approach for designing high-performance carbonylation catalysts. The synthesized Pd3P/SiO2 (5 wt.%) catalyst was characterized via PXRD, HAADF-STEM, HRTEM, EDX, CO chemisorption and ICP-AES analysis. The incorporation of phosphorus into the palladium matrix, which results in the formation of a Pd3P phase, enhanced the intrinsic catalytic activity in the alkoxycarbonylation of aryl halides by more than two-fold compared to a traditional purely Pd-based heterogeneous catalyst. Moreover, Pd3P/SiO2 (5 wt.%) outperformed many reported heterogeneous catalysts as well as some commonly used homogeneous catalysts. The exceptional performance of palladium phosphide nanoparticles can be attributed to highly active and uniformly distributed Pd sites separated by phosphorus. This work highlights the potential of element synergy in developing highly efficient carbonylation catalysts by exploring Pd-P system in the alkoxycarbonylation reaction.