Integrating Hydrogenated TiO₂-Modified Carbon-Supported PtRu Anodes and Fe-N-C Cathodes for High-Performance Direct Methanol Fuel Cells

Direct methanol fuel cells (DMFCs) have attracted significant interest owing to their high energy density and ease of handling methanol. However, commercialization is challenged by the sluggish methanol oxidation kinetics of the PtRu anode and methanol crossover to the cathode. Although platinum group metal-free (PGM-free) cathode catalysts exhibit promising methanol tolerance, their performance is limited by cathode flooding due to methanol crossover. This study investigates various anode carbon support architectures modified with hydrogenated TiO₂ to address methanol crossover issues in PGM-free cathodes and to improve the activity and durability of PtRu electrocatalysts. Systematic three-electrode studies and accelerated stress tests reveal the significant effect of different anode carbon supports on the activity and durability of PtRu electrocatalysts toward methanol and CO oxidation. DMFCs integrated with a PGM-free Fe-N-C cathode and a PtRu anode catalyst on the TiO₂-modified carbon nanotube demonstrate peak power densities of 216.6 and 178.6 mW/cm² in oxygen and air feed at 100 °C, respectively, among the highest reported. The performance remains unchanged with up to 4.0 M methanol feed for the carbon nanotube-supported anode, unlike conventional carbon support causing cathode flooding. This study reveals the importance of the anode carbon support architecture in mitigating methanol crossover, which is crucial for addressing cathode flooding in PGM-free cathodes, and improving the PtRu catalyst activity and durability.