Pore Expansion\nof N‑Doped Carbon as Support\nof Pd Catalyst for Accelerated Formic Acid Dehydrogenation

Formic acid offers a fascinating medium for hydrogen\nstorage and\ntransport, and Pd@carbon catalysts are the most common catalysts for\ncatalyzing the release of hydrogen from formic acid (dehydrogenation).\nBiomass-derived carbon is advantageous over other supports in view\nof cost, sustainability, and easy modification. Nitrogen (N) doping\nof carbon can improve the activity of a carbon-supported Pd catalyst,\nbut the concurrently deteriorated porosity of carbon inhibits it from\nreaching the full potential. Herein, the pores of N-doped wood-derived\ncarbon were expanded by a novel alkali/air coactivation method so\nas to enhance further the activity of Pd@carbon catalyst for formic\nacid dehydrogenation. After investigation of the influence of N doping\nand coactivation conditions, the N-doped porous carbon (NPC) with\ndeveloped porosity (SA<sub>BET</sub> = 956 m<sup>2</sup>·g<sup>–1</sup>, and SA<sub>meso</sub> = 295 m<sup>2</sup>·g<sup>–1</sup>) was produced at optimized conditions. The Pd@NPC\ncatalyst with well-distributed ultrafine Pd nanoparticles (0.4–1.4\nnm) was synthesized by taking advantage of both N doping and expanded\npores (especially mesopores) of NPC. Subsequently, a turnover frequency\nof 446 h<sup>–1</sup> was obtained using this Pd@NPC catalyst\nfor additive-free formic acid dehydrogenation at 303 K. Thus, formic\nacid dehydrogenation was accelerated by expanding the pores of N-doped\nbiomass-derived carbon that acted as a support of Pd catalysts.