Enhanced electrocatalytic performance for methanol oxidation with a Magnéli phase molybdenum oxide/Pt-black composite

• Crystallised Magnéli phase Mo4O11 used as a co-catalyst support to enhance MOR.
• Multiple Mo valence states coexist in Mo4O11.
• These promote hydrogen spillover and oxygen buffering in the Pt/Mo4O11 catalyst.
• The catalyst shows improved poisoning tolerance and electrocatalytic activity.

A composite electrocatalyst composed by prepared Magnéli phase Mo4O11 and Pt-black (Pt/Mo4O11) was found with highly effective for the methanol oxidation reaction (MOR). Cyclic voltammetry (CV) result showed that the mass activity for the forward peak (If) of Pt/Mo4O11 was determined to be 722.20 mA mg−1Pt, e.g., about twice of the mass activity of the stand-alone Pt-black. This suggested that the electrocatalytical reactivity is improved when the crystallised Mo4O11 assists for methanol oxidation. It is also found that the peak current ratio of the forward versus the reverse (If/Ib) is 1.21 for Pt/Mo4O11 and 0.81 for Pt/C, respectively. X-ray photoelectron spectroscopy (XPS) results indicated that different valence states of molybdenum coexist in Mo4O11; this promotes both hydrogen spillover and oxygen buffering effects. The synergistic effects of Pt and Mo4O11 on the electrochemical properties represent a critical advantage of the Pt/Mo4O11 catalyst for anti-poisoning towards the intermediates in the MOR.

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