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.