The direct methanol fuel cells (DMFCs) that use liquid and renewable methanol as fuel supplies have attracted significant attention since the last two decades. The DMFCs displayed advantages, such as convenient storage and transportation of fuels, high specific energy density at low operating temperature, and flexible design of the fuel cell devices. In this research, Mo4O11 polycrystals were prepared and used as the electrocatalysts to decrease the Pt loading. Our study indicated that the composite of magnéli Mo4O11 and Pt-black (Pt/Mo4O11) was found to exhibit high reactivity towards methanol oxidation reaction (MOR). Compared with the conventional carbonaceous supports, these Pt/Mo4O11 catalyst also displayed excellent poisoning tolerance toward intermediate products generated during the MOR. The electrochemical behavior of the catalyst was measured by the cyclic voltammetry (CV) in an acidic methanol solution. It was found that the peak current ratio of the forward versus the reverse (If/Ib) is 1.21 for Pt/Mo4O11catalyst and 0.81 for Pt/C, respectively. It can be concluded that the electrocatalytical reactivity was advanced when the quasi-two-dimensional crystallized Mo4O11 was used for methanol oxidation due to its high electronic conductivity. The mass activity (If) for the forward peak of Pt/Mo4O11 was determined to be 722.20 mA×mg-1Pt, about twice of mass activity (356.10 mA×mg-1Pt) of the stand-alone Pt-black. The XPS results indicated that different valence states of molybdenum are co-existing in Mo4O11 polycrytals. This multi-oxidation state of Mo promotes both hydrogen spillover and oxygen buffering effects in Pt/Mo4O11.

Structural characterization and electrochemical performance of Mo4O11 and Pt-black composite used to enhance methanol oxidation

251st National Meeting (2016)

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