Synthesis of Heteroatom Rh-ReOx Atomically Dispersed Species on Al2O3 and Their Tunable Catalytic Reactivity in Ethylene Hydroformylation

Atomically dispersed late transition metal catalysts exhibit distinct catalytic reactivity and selectivity compared to metal clusters in many reactions. Realizing the potential benefits of these catalysts requires active site uniformity and control of their local environment. Here, we propose a catalyst synthesis route for manipulating the local environment of atomically dispersed metal active sites. This was achieved via the targeted deposition of Rh precursors near atomically dispersed ReOx on γ-Al2O3 using electrostatic interactions. CO probe molecule IR spectroscopy and aberration corrected scanning transmission electron microscopy suggested that Rh could be preferentially located near a single ReOx species or multiple ReOx species by controlling ReOx loading. Rh-ReOx interactions promoted catalytic reactivity and selectivity for ethylene hydroformylation. Kinetic measurements suggested that ReOx species withdrew charge from Rh, weakening Rh-CO interactions, which promoted the concentration of vacant ...