Preparation of carbon nanomaterials with controlled size and morphology and their application as catalyst support material for PEMFC

摘要

Carbon nanotubes (CNTs) and carbon nanofibers (CNFs) were prepared by thermal CVD process using Ni-MgO catalyst. Mixture of Ni(OH)(2)-Mg(OH)(2) used as the precursor of catalyst was treated by mechanochemical process. CNTs with diameter 25 nm and 15 nm, twisted CNFs with diameter 65 nm and 100 nm, and straight CNFs with 70 nm were synthesized. After purification, they were used as the electrode platinum support for fuel cell application. 20% Pt was loaded on the CNTs and CNFs using H2PtCl6 and NaBH4, and fuel cell electrode performance was evaluated. The fuel cell performance with twisted CNFs was found to be better than that with straight CNFs, and performance of CNTs and CNFs with smaller diameter was better than that of bigger one. Best performance was obtained using twisted CNFs with diameter 65 nm, and a fuel cell voltage of 645 mV was obtained at a current density of 500 mA/cm(2). The better performance of twisted CNFs and CNTs can be attributed to the specific interaction between Pt and CNFs with specific surface conformation, and smaller size which leads to higher conductance.