Amine-Functionalized Carbon Bowl-Supported Pd-La(OH) for Formic Acid Dehydrogenation.

Formic acid (HCOOH, FA) is emerging as an appealing carrier for hydrogen storage owing to its renewability, a high volumetric capacity of 53 g H/L, and convenient storage/transportation as a liquid. It is highly desired but still a challenge to search highly efficient catalysts to realize hydrogen evolution from FA. Here, monodispersed and ultrasmall Pd-La(OH) nanoparticles (NPs) anchored on amine-functionalized N-doped porous carbon bowl (N-PCB-NH) substrates have been fabricated through a facile wet chemistry approach. As a result of the ultrafine size of Pd-La(OH) NPs (1.6 nm), the deprotonation ability of La(OH) and amine groups, and the strong metal-support interaction between Pd-La(OH) and N-PCB-NH, the as-prepared Pd-La(OH)/N-PCB-NH catalyst exhibits 100% H selectivity and exceptional catalytic property with a high turnover frequency value up to 9585 h for FA dehydrogenation at 323 K, which is superior to most of the heterogeneous catalysts ever reported. Kinetic isotope effect measurements demonstrate that the C-H bond cleavage is a rate-determining step in the FA dehydrogenation reaction as compared to the O-H bond dissociation. This work presents a feasible approach to synthesize supported ultrafine metal NP catalysts with porous bowl structures for H generation from FA.