Reversing the Catalytic Selectivity of Single-Atom Ru via Support Amorphization.

Supported single-atom catalysts (SACs), with the extremely homogenized active sites could achieve high hydrogenation selectivity toward one of the functional groups coexisting in the reactant molecule. However, as to the target group, the control of selective recognition and activation by SACs still remains a challenge. Herein, the phase engineering of the support is adopted to control the chemo-recognition behavior of SACs in selective hydrogenation. Single-atom Ru on amorphous porous ultrathin TiO nanosheets (Ru/a-TiO) is constructed, in which Ru is more positively charged than that in the crystalline counterpart (Ru/c-TiO). Moreover, in the nitro/vinyl selective hydrogenation process, Ru/a-TiO shows superior nitro selectivity, opposite to the vinyl selectivity of Ru/c-TiO. Density functional theory calculations for single-atom Ru of different charge states show that the reactant adsorption configuration could be inverted in the amorphous TiO, accounting for the chemo-recognition behavior controlled by the phase of support.