Amine-functionalized hierarchically porous carbon supported Pd nanocatalysts for highly efficient H2 generation from formic acid with fast-diffusion channels

Abstract

Formic acid (FA) has come to be considered a potential candidate for hydrogen storage, and the development of efficient catalysts for H2 releasing is crucial for realizing the sustainable process from FA. Herein, we have developed the ultrafine Pd nanoparticle (NPs) with amine-functionalized carbon as a support, which was found to show an excellent catalytic activity in H2 generation from FA dehydrogenation. The synergetic mechanism between amine-group and Pd active site was demonstrated to facilitate H2 generation by β-hydride elimination. Moreover, the texture of support for Pd NPs also plays an important role in determining the reactivity of FA, since the diffusion of gaseous products makes the kinetics of diffusion as a challenge in this high performance Pd catalysts. As a result, the as-prepared Pd/NH2-TPC catalyst with the small sized Pd nanoparticles and the hierarchically porous structures shows a turnover of frequency (TOF) value of 4312 h−1 for the additive-free FA dehydrogenation at room temperature, which is comparable to the most promising heterogeneous catalysts. Our results demonstrated that the intrinsic catalytic activities of active site as well as the porous structure of support are both important factors in determining catalytic performances in H2 generation from FA dehydrogenation, which is also helpful to develop high-activity catalysts for other advanced gas-liquid-solid reactions systems.