The identification of highly active heterogeneous catalysts to replace their homogeneous counterparts remains a challenge in the case of organic catalysts, especially polymers, in highly viscous reaction systems. In this work, we designed and synthesized a novel, solid-supported, and heterogeneous pseudo-single atom Pt catalyst with high activity and recyclability. Superparamagnetic Fe₃O₄-SiO₂ core–shell nanoparticles (NPs) were used as the substrate. The functionalization of the SiO₂ shell with silane coupling agents containing vinyl groups allows stabilizing Pt on the SiO₂ surface through complexation. The as-prepared pseudo-single atom Pt displays high activity in the hydrosilylation of allyl-terminated polyether with polymethylhydrosiloxane and could be easily collected by applying a magnetic field. The Pt/vinyl/SiO₂/Fe₃O₄ catalyst can be reused for up to four reaction cycles without appreciable decrease in activity. This work demonstrates a novel strategy for the design of pseudo-single atom noble metal catalysts for processes in high-viscosity media.