Immobilizing Pd nanoparticles on amine-functionalized yolk-shell mesoporous silica nanospheres for efficient H2 production from formic acid dehydrogenation

Ultrafine Pd nanoparticles (NPs), immobilized within amine-functionalized yolk-shell mesoporous silica nanospheres (YSMSNs), have been elaborately prepared to facilitate the highly effective formic acid (FA) dehydrogenation. The optimized Pd/YSMSNs-NH2(10-3, 10 wt% Pd loading and 3 mL of amine treatment on YSMSNs), displays the extraordinary turnover frequency (TOF, 9108 h-1) and stability at 343 K, achieving 100% FA conversion and H2 selectivity, which is higher than other documented heterogeneous catalysts. The radially oriented pore channels can facilitate the mass transfer of reactants. The amine groups on the YSMSNs-NH2 effectively promote the cleavage of the O-H bond within FA. Furthermore, the ultrafine size of the Pd NPs and their high dispersion on the YSMSNs-NH2 provide a wealth of active sites for catalysis. Lastly, the metal-support interaction (MSI) between the Pd NPs and YSMSNs-NH2 further enhances the catalytic performance. This work provides a new strategy into developing effective silica-based heterogeneous catalysts for FA dehydrogenation.