Synthesis and electrocatalytic performance of multi-component nanoporous PtRuCuW alloy for direct methanol fuel cells

Abstract

We have prepared a multi-component nanoporous PtRuCuW (np-PtRuCuW) electrocatalyst via a combined chemical dealloying and mechanical alloying process. The X-ray diffraction (XRD), transmission electron microscopy (TEM) and electrochemical measurements have been applied to characterize the microstructure and electrocatalytic activities of the np-PtRuCuW. The np-PtRuCuW catalyst has a unique three-dimensional bi-continuous ligament structure and the length scale is 2.0 ± 0.3 nm. The np-PtRuCuW catalyst shows a relatively high level of activity normalized to mass (467.1 mA mgPt-1) and electrochemically active surface area (1.8 mA cm-2) compared to the state-of-the-art commercial PtC and PtRu catalyst at anode. Although the CO stripping peak of np-PtRuCuW 0.47 V (vs. saturated calomel electrode, SCE) is more positive than PtRu, there is a 200 mV negative shift compared to PtC (0.67 V vs. SCE). In addition, the half-wave potential and specific activity towards oxygen reduction of np-PtRuCuW are 0.877 V (vs. reversible hydrogen electrode, RHE) and 0.26 mA cm-2, indicating a great enhancement towards oxygen reduction than the commercial PtC.