Titanium carbide and its core-shelled derivative TiC@TiO2 as catalyst supports for proton exchange membrane fuel cells

Both TiC and core-shelled TiC@TiO2 are investigated as catalyst supports for proton exchange membrane fuel cells (PEMFCs). TiC is thermally stable, possesses both low solubility in sulphuric acid and high electronic conductivity. However, TiC undergoes irreversible electrochemical oxidation in dilute perchloric acid and the operating potential range of 0–1.2 VRHE. TiC@TiO2 core–shell composite is found to be more stable than TiC. Both these materials are used as supports for Pt and Pt–Pd alloy catalysts (Pt/TiC, Pt3Pd/TiC and Pt3Pd/TiC@TiO2) and are synthesized by microwave-assisted polyol process. The catalytic activities of both Pt3Pd/TiC and Pt3Pd/TiC@TiO2 toward the oxygen reduction reaction (ORR) are much higher than those for Pt/TiC. Accelerated durability tests show that TiC supported catalysts are not electrochemically stable. The corresponding TiC@TiO2 supported catalyst is more stable than that supported by TiC, indicating that with a protective oxide layer on the TiC core, TiC@TiO2 is a promising PEMFC catalyst support.