Pd Nanoparticles Supported on N- and P‑Co-doped Carbon as Catalysts for Reversible Formate-Based Chemical Hydrogen Storage

Efficient and reversible hydrogen-storage systems derived from liquid organic compounds are promising alternatives for sustainable energy supplies. Here, we report a Pd nanoparticle catalyst supported on porous carbon co-doped with nitrogen and phosphorous for reversible formate-based chemical hydrogen storage. The materials showed good catalytic performance for both formate dehydrogenation and bicarbonate hydrogenation. The N,P-dual-doped carbon was fabricated by directly pyrolyzing a mixture of 1,10-phenanthroline and triphenylphosphine. Initial density functional theory (DFT) studies suggested that N and P co-dopants played synergistic roles in modulating the electronic properties of the carbon support. X-ray photoelectron spectroscopy and CO pulse adsorption experiments revealed that the resulting metal–support interactions enriched the electron density at the Pd active site. This promoted the activity of Pd nanoparticles for formate dehydrogenation with a turnover frequency of 3254 h^–1, and a high formate yield exceeding that of individual N-doped or P-doped catalysts was also obtained for the hydrogenation of bicarbonate.