High-temperature-treated multiwall carbon nanotubes for hydrogen evolution reaction

We investigated the hydrogen evolution reaction (HER) properties of multi-wall carbon nanotubes (MWCNTs) treated at extremely high temperature (2600 °C). The heat treatment not only improves the crystallinity of the MWCNTs, but also reduces the carbon-oxygen (CO) bonding as it is replaced by the defect-carbon (sp3 and CH) bonding. These modifications in the heat treated MWCNT structure lead to the increase of electrochemical charge transfer. The heat treatment of MWCNTs in the composite with Pt (MWCNT-Pt composite) further facilitates electrocatalysis. The MWCNTs-Pt composite shows strong enhancement in the HER performance with an onset of overpotential of −0.04 V vs reversible hydrogen electrode and a Tafel slope of 10.9 mV/decade. This performance is indeed better than that of Pt, which is the best working material for HER.