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.