Hydrogen production from formic acid dehydrogenation over a Pd supported on N-doped mesoporous carbon catalyst: A role of nitrogen dopant

[Display omitted] •Nitrogen-doped mesoporous carbon (NMC) was prepared with various nitrogen contents.•Pd-impregnated on NMC catalysts were tested for formic acid dehydrogenation (FAD).•The nitrogen dopants accelerated the catalytic activity of Pd/NMC for the FAD.•The excess nitrogen dopant raised the activation barrier of the FAD.•The optimum nitrogen-doping was required for efficient catalytic improvement. Nitrogen dopant is known to promote the activity of active metal in various catalytic reactions. Herein, the role of nitrogen dopant in formic acid dehydrogenation was investigated by synthesizing nitrogen-doped mesoporous carbon (NMC) with different nitrogen contents and impregnating Pd particles on these supports (Pd/NMC). The nitrogen dopant made Pd particles small and modified the electronic state of Pd, resulting in the enhanced formic acid dehydrogenation activity. However, an excess interaction between Pd and nitrogen dopant raised the activation barrier of the formic acid dehydrogenation. This experimental result is consistent with the previously reported computational prediction. Hence, this study suggests that the optimum nitrogen doping is required to efficiently improve the catalytic activity for hydrogen production from formic acid. In addition, the hydrogen production rate was further improved by using sodium formate as an additive, resulting in the TOF value of 4821 h−1 at 65 °C.