High-Density Dispersion of Atomic Pt (Ru, Rh, Pd, Ir) Induced by Meso-Stable Penta-Coordinated Fe^III in the Topological Transformation of Layered Double Hydroxides

Atomically dispersed metal sites afford high activity or selectivity in many heterogeneous catalytic reactions. It is still an open challenge to achieve a high-density dispersion of atomic metals. Herein, this work demonstrates a facile strategy to boost the dispersion density of atomic metals by the induction of meso-stable lattice distortion sites in the topological transformation of layered double hydroxides (LDHs). Meso-stable penta-coordinated Fe-III, resulting from the difference in the thermal stability between Mg-OH and Fe-OH in a LDH lattice, is utilized from MgFe-LDHs as anchoring sites for atomic Pt. The dispersion density of atomic Pt reaches 2.0 Pt-1/nm(2). This strategy in the topological transformation of LDHs has been successfully extended to prepare high-density atomic Ru, Ir, Pd, and Rh. In both catalytic oxidation of HCHO and hydrogenation of furfuryl alcohol, high-density atomic Pt affords high turnover frequency (TOF) by the simultaneous high-efficiency activation of multimolecules on adjacent atomic Pt sites. In HCHO oxidation, high-density atomic Pt affords high mass activity under a high concentration, high space velocity, and low temperature. In furfuryl alcohol hydrogenation, high-density atomic Pt affords high mass activity while retaining >99% selectivity of 2-methylfuran.