Platinum/Tantalum Carbide Core-Shell Nanoparticles with Sub-Monolayer Shells for Methanol and Oxygen Electrocatalysis

Core-shell architectures provide great opportunities to improve catalytic activity, but achieving nanoparticle stability under electrochemical cycling remains challenging. Herein, core-shell nanoparticles comprising atomically thin Pt shells over earth-abundant TaC cores are synthesized and used as highly durable electrocatalysts for the methanol oxidation reaction (MOR) and the oxygen reduction reaction (ORR) needed to drive direct methanol fuel cells (DMFCs). Characterization data show that a thin oxidic passivation layer protects the TaC core from undergoing dissolution in the fuel cell-relevant potential range, enabling the use of partially covered Pt/TaC core-shell nanoparticles for MOR and ORR with high stability and enhanced catalytic performance. Specifically, at the anode the surface-oxidized TaC further enhances MOR activity compared to conventional Pt nanoparticles. At the cathode, the Pt/TaC catalyst feature increases tolerance to methanol crossover. These results show unique synergistic advantages of the core-shell particles and open opportunities to tailor catalytic properties for electrocatalytic reactions. Pt/TaC core-shell nanoparticles are synthesized and applied as electrocatalysts for direct methanol fuel cell reactions. TaC core not only manifests an excellent stability, but also contributes to an enhanced methanol-oxidation activity. The capability to handle methanol also leads to improved oxygen-reduction performance under the presence of methanol, showing the robustness of Pt/TaC catalysts regarding the methanol crossover issue. image