RuO_{: X}-decorated multimetallic hetero-nanocages as highly efficient electrocatalysts toward the methanol oxidation reaction

Direct methanol fuel cell technology awaits the development of highly efficient and robust nanocatalysts driving the methanol oxidation reaction (MOR) in a CO poisoning-free fashion. Thus far, various Pt-based alloy nanoparticles have been studied as electrocatalysts toward the MOR, and it has been found that the introduction of dopants such as Ru and Cu to Pt has been particularly successful in mitigating the CO poisoning problem. Herein, we report a facile synthesis of Ru-branched RuPtCu nanocages that involves in situ formation of Ru-doped PtCu nanoparticles and subsequent outgrowth of Ru branches by insertion of additional Ru precursors. We show that the electrocatalytic activity and stability of Ru branched RuPtCu ternary nanocages toward the MOR are greatly improved compared to those of PtCu/C and RuPtCu/C counterparts and state-of-the-art PtRu/C and Pt/C catalysts, mainly due to the synergy between the CO-tolerant RuO_x phase and the highly open and robust RuPtCu nanoframe.