%0 Journal Article
%T Microwave-Assisted Synthesis of Classically Immiscible Ag每Ir Alloy Nanoparticle Catalysts
%J -
%D 2018
%R https://doi.org/10.1021/acscatal.8b02103
%X We present the synthesis of Ag每Ir alloys in the form of solid-solution nanoparticles (NPs). Ag and Ir are classically immiscible in the bulk and therefore the physical properties of Ag每Ir alloys are unknown. A convenient microwave-assisted, solution-phase method that employs readily available Ag(NO3) and IrCl3 precursors enables the preparation of small (2.5每5.5 nm) Ag每IrNPs with alloyed structures. AgxIr(100每x)NPs can be obtained by this method between x = 6每31. The Ag每IrNPs resist dealloying upon heating up to 300 ∼C. Ir-rich Ag每IrNPs dispersed on amorphous silica are significantly more active gas-phase alkene hydrogenation catalysts than pure IrNPs. Density functional theory (DFT) and theoretical modeling studies reveal that the Ag每IrNPs〞which are consistently larger than monometallic IrNPs prepared under the same conditions〞have comparatively fewer strong H-binding edge sites. This promotes faster H atom transfer to coadsorbed alkenes. Ag每IrNPs supported on amorphous Co3O4 show a linear composition dependence in the selective hydrogenation of C汽O versus C汽C bonds: more Ag-rich Ag每IrNPs are more selective toward C汽O hydrogenation of the 汐,汕-unsaturated aldehyde crotonaldehyde, yielding the industrially desirable crotyl alcohol. Furthermore, deposition of Ag每IrNPs inside Co3O4 mesopores results in an additional ‵56% selectivity enhancement
%U https://pubs.acs.org/doi/10.1021/acscatal.8b02103