Chemical activation of Vulcan® XC72R to be used as support for NiNbPtRu catalysts in PEM fuel cells

摘要

Carbon supports are widely used as electro-catalyst supports in low-temperature fuel cells. As the structure and physical properties of these supports have an influence on their properties, the aim is to find a simple method to obtain supports with suitable porosity, good conductivity and stable in fuel cell environment. In this work, a method for chemical activation of Vulcan~® XC72R has been developed to obtain a support for Ni_(59)Nb_(40)Pt_(0.6)Ru_(0.4) catalysts in MEAs. With fixed work conditions such as carbon/KOH ratio, N_2 flow, heating rate, time and treatment temperature as a starting point, different washing procedures to remove the Potassium compounds for the resulting material have been devised. Results show that the activation treatment improves the behavior of the supports and the importance of the washing method on the removal of the alkaline compounds. Samples washed using HC1 and HNO_3 solutions (VKCl and VKN) show much better results than those that were solely washed using deionized water (VKOH). This could be explained by the fact that Potassium compounds with low solubility in water could be blocking the access to some of the created porosity and removal could be improved in the presence on an acid solution.