Effect of activation/purification of multiwalled carbon nanotubes (MWCNTs)on the activity of non-platinum based hypo-hyper d-electrocatalysts for hydrogen evolution

摘要

Commercial multiwalled carbon nanotubes (MWCNTs) were used as a catalyst support for non-platinumudhypo-hyper d-electrocatalysts. In order to improve the performance of these catalysts, activation/udpurification of MWCNTs in acid medium (HNO3) was carried out. The physical and surface changes ofudMWCNTs were investigated by DTA/TGA analysis, Raman spectroscopy, and cyclic voltammetry.udStructural changes of the electrocatalysts were observed by infrared spectroscopy and SEM. Their use asuda support for electrocatalysts for hydrogen evolution was demonstrated, and shown to be more suitableudcompared to the traditional carbon support material � carbon black (Vulcan XC-72). The electrocatalysts consisted of 10% Co + 18% TiO2 + MWCNTs. Activation/purification removes the amorphous carbon phase in theMWCNTs. As a result of both shortening and opening of carbon nanotubes, better dispersion of metallic particles (the active catalytic centers) was achieved. Thus, trans-particle and inter-particle porosity of the electrocatalytic material was improved, implying increase of catalytic activity forudhydrogen evolution.