SiCTiC as catalyst support for HT-PEMFCs. Influence of Ti content

Abstract

This manuscript studies the influence of the titanium content on the main physicochemical properties of a binary silicon carbide- titanium carbide raw material (SiCTiC), to be used as catalyst support in High Temperature PEM fuel cells (HT-PEMFCs). Three SiCTiC samples with 10, 20 and 30%TiC molar content were studied, analysing the most relevant parameters to be used as catalyst support. First, BET surface area, electrical conductivity, thermal resistance in hot acidic media, and electrochemical resistance were the parameters studied. Results achieved show a decreasing of the BET surface area with the increasing of TiC content, but also an enhancement of the electrical conductivity. All materials studied demonstrated high thermal and electrochemical resistance. After the preliminary physicochemical characterization, Pt-based catalysts with a 40%wt. metal content were synthesized using different carbides studied. Platinum particle and crystallite size, real platinum content and distribution, and electrochemical surface area (ECSA) were the parameters studied. SiCTiC with 30%Pt content exhibited a poor Pt dispersion and ECSA value, achieving better results with catalysts prepared using SiCTiC supports with lower Ti content, resulting on good candidates to be used in this kind of technology.