Abstract: In this paper, 5,10,15,20-tetraphenylporphyrin complexes of transition metals (Co, Cu, Mn, Ni, Fe) were prepared and the metalloporphyrin/multi-walled carbon nanotubes composites for electrocatalytic hydrogen evolution reaction (HER) were fabricated by non-covalent interactions. The results showed that the composite CoTPP/MWCNTs exhibit the best electrocatalytic hydrogen evolution reaction performance when the loading of metalloporphyrin was 10 wt%. The UV-Vis DRS and XPS results showed that there are strong π-π interactions between the metalloporphyrin and the multi-walled carbon nanotubes. The catalytic activities of the metalloporphyrin/multi-walled carbon nanotubes composites are in the order of Co > Cu > Mn > Ni > Fe. Among them, the CoTPP/MWCNTs show an overpotential of 631 mV at the current density of 10 mA/cm2 and the smallest Tafel slope (161.3 mV/dec) as well as charge transfer resistance (10.3 Ω), suggesting the utilisation of the non-covalent combination of metalloporphyrin with multi-walled carbon nanotubes is an effective way to construct composite electrocatalysts.

Key words: Metalloporphyrin, Multi-walled carbon nanotubes, Noncovalent interaction, Electrocatalysis, Hydrogen evolution reaction