Ultralow platinum-loading PtPdRu@PtRuIr/C catalyst with excellent CO tolerance and high performance for the methanol oxidation reaction

Carbon-supported PtPdRuIr, Pd@PtRuIr, PtPd@PtRuIr, and PtPdRu@PtRuIr catalysts were prepared by a colloidal method and their catalytic activities to the methanol oxidation reaction in the acidic media were extensively investigated at room temperature. The catalysts were characterized by transmission electron microscopy and X-ray diffraction techniques, and their electrochemical behavior was evaluated by the cyclic voltammetry. The PtPdRu@PtRuIr/C catalyst is found to yield much higher electrocatalytic activity than the other ones and the commercial catalyst. For example, the Pt metal mass-specific activity of this PtPdRu@PtRuIr/C (Pt content 10 wt%, 1.7 mA·cm−2·mg−1) electrocatalyst is ~3-fold higher than that of the commercial JM 40 % Pt/C (0.6 mA·cm−2·mg−1) electrocatalysts, and the If/Ib ratio of PtPdRu@PtRuIr/C is 1.6, which is higher than that of the JM 40 % Pt/C (0.9). The improvement may result from the high dispersion of the active metal catalyst and the synergistic effect between the PtRuIr and PtPdRu layers. It is thus concluded that the pseudo-core–shell structure could significantly improve the methanol electro-oxidation activity and CO tolerance of the electrocatalyst.