Orientated carbon nanotubes boosting faster charge transfer for bifunctional HER and OER

Orientated Carbon nanotubes would expose more active sites and have better electrical conductivity, while most of the carbon nanotubes are disordered, so it is necessary to align with the aid of external force. Hence, we obtain the stretchable films (denoted as PMC) by casting the solution of hydrothermal MWCNTs (ho-MWCNTs) and poly (vinyl alcohol) (PVA), following the Ni(OH)(2) deposited on PMC (denoted as PMC/Ni). XPS and XRD confirmed the charge transfer between ho-MWCNTs and PVA, which means generation of electronic delocalization center. Furthermore, the alignment of ho-MWCNTs could be observed by SEM. Meanwhile, PMC/Ni exhibited excellent catalytic performance for OER and HER in 1 M KOH. It only require 320 mV to achieve 20 mA cm(-2) for OER and a low overpotential of -219 mV to achieve 10 mA cm(-2) for HER in 1 M KOH. The results verify that orientated ho-MWCNTs have a positive effect in promoting catalytic performance by promoting to faster electron transfer and more active sites. Hence, we believe that the catalytic performance of other hollow-tubes materials would show a strong relationship with the orientation, which needs more efforts to research. (C) 2020 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.