Abstract: | Recently, a facile method for the synthesis of size‐monodisperse Pt, Pt3Sn, and PtSn intermetallic nanoparticles (iNPs) that are confined within a thermally robust mesoporous silica (mSiO2) shell was introduced. These nanomaterials offer improved selectivity, activity, and stability for large‐scale catalytic applications. Here we present the first study of parahydrogen‐induced polarization NMR on these Pt‐Sn catalysts. A 3000‐fold increase in the pairwise selectivity, relative to the monometallic Pt, was observed using the PtSn@mSiO2 catalyst. The results are explained by the elimination of the three‐fold Pt sites on the Pt(111) surface. Furthermore, Pt‐Sn iNPs are shown to be a robust catalytic platform for parahydrogen‐induced polarization for in vivo magnetic resonance imaging. |