Support Engineering for the Stabilisation of Heterogeneous Pd₃P-Based Catalysts for Heck Coupling Reactions

Herein we report the use of a supported Pd3P catalyst for Heck coupling reactions. For the stabilisation of Pd3P and Pd, as reference system, the silica support material was modified via phosphorus doping (0.5 and 1 wt % P). Through this so-called support engineering approach, the catalytic activity of Pd3P was clearly enhanced. Whereas an iodobenzene conversion of 79 % was witnessed for Pd3P@SiO2 in the coupling of styrene and iodobenzene in 1 h, 90 % conversion could be achieved using Pd3P@1P-SiO2. This improved catalytic activity probably stems from an electronic modulation of the support surface via the introduction of phosphorus. Simultaneously, the recyclability was boosted and the Pd3P@1P-SiO2 catalyst has shown to maintain its catalytic activity over several recovery tests. Hereby, metal leaching could almost be suppressed completely to 3 % by the use of a P-modified silica support.