Fundamental Mechanisms of Reversible Dehydrogenation of Formate on N-Doped Graphene-Supported Pd Nanoparticles

Reversible formate (HCOO–) dehydrogenation and bicarbonate (HCO3–) hydrogenation would be desirable for the utilization and storage of hydrogen (H2) as an effective energy carrier. Carbon-supported Pd-based nanoparticles demonstrated enormous competitive advantages for these reactions. However, the fundamental mechanisms underlying these reversible reactions have not yet been elucidated. Herein, we report the reaction pathways for reversible reactions on a Pd-based catalyst using density functional theory (DFT) calculations and propose key factors for improving the reaction efficiency. As the first essential step, the difficulty in the conventional DFT modeling, that is simulation of an anion environment caused by HCOO–, was overcome by designing two-sided Pd12 nanoclusters supported on graphene (Pd12NC-G) with extra electrons. Using Pd12NC-G, we demonstrated that the key factor determining the potential limiting steps for the reversible reaction was desorption of hydrogen in HCOO– dehydrogenation (1.24 e...