Monodisperse Copper Nanoparticles on Porphyrin-Derived Fe–N-Doped Carbon for Hydrogen Generation from Ammonia Borane

Ultrafine copper nanoparticles (Cu NPs) on iron-nitrogen doped carbon (Fe–N–C) were prepared via an electrochemically facial route. Porphyrins were pyrolyzed in the presence of iron-oxalate and sulfur to obtain Fe–N–C. Incorporation of the CN^– ligands serves as basis which assist the coordination and concentration of Cu ions on the Fe–N–C surface. Then, electrochemical reduction of Cu(II) to Cu(0) was accomplished to give Cu NPs. The ultrafine Cu NPs (2 nm in diameter) are promisingly dispersed on the surface of Fe–N–C due to their interaction with CN-groups. The catalytic activity of Fe–N–C, and Cu NPs were compared with Cu/Fe–N–C for the hydrolysis reaction of ammonia borane (AB, NH₃BH₃) under ambient atmosphere pressure at room temperature. The activation energy of Cu/Fe–N–C for the hydrolysis of AB was obtained 33±1 kJ mol^–1 which is lower than other Cu-based catalysts reported previously. Moreover, the recycle tests exhibit that the Cu/Fe–N–C retains almost 85% of its initial catalytic activity even after fifth catalytic reuse. The high performance and low synthetic cost of Cu/Fe–N–C may make it possible to be used as promising hydrogen storage materials for AB.