Pd-MnO_x nanoparticles dispersed on amine-grafted silica: Highly efficient nanocatalyst for hydrogen production from additive-free dehydrogenation of formic acid under mild conditions

摘要

Herein we report the development of a new highly active, selective and reusable nanocatalyst for additive-free dehydrogenation of formic acid (HCOOH), which has great potential as a safe and convenient hydrogen carrier for fuel cells, under mild conditions. The new catalyst system consisting of bimetallic Pd-MnO_x nanoparticles supported on aminopropyl functionalized silica (Pd-MnO_x/SiO2-NH2) was simply and reproducibly prepared by deposition-reduction technique in water at room temperature. The characterization of Pd-MnO_x/SiO2-NH2 catalyst was done by the combination of multipronged techniques, which reveals that the existence of highly crystalline individually nucleated Pd(0) and MnO_x nanoparticles (d_(mean) =4.6 ± 1.2 nm) on the surface of aminopropyl functionalized silica. These supported Pd-MnO_x nanoparticles can catalyze the additive-free dehydrogenation of formic acid with record activity (TOF= 1300h~(-1)) at high selectivity (>99%) and conversion (>99%) under mild conditions (at 50°C and under air). Moreover, easy recovery plus high durability of these supported Pd-MnO_x nanoparticles make them a reusable heterogeneous catalyst in the additive-free dehydrogenation of formic acid.