Electron-Enriched Pt Induced by MnO2 Structural Variation Achieving Low-Alkalinity Methanol Electrooxidation
Achieving high-efficiency electrooxidation of methanol (MOR) under low alkalinity is critical for the industrial application of direct methanol fuel cells. This challenge can be addressed by modulating the electron density of nanosized Pt particles via the support’s exchange effect. Herein, an electron-enriched Pt catalyst (Pt/Mn3O4) was successfully synthesized through the structural tuning of MnO2. The Pt/Mn3O4 catalyst exhibits a superior performance, delivering a mass activity of 1150 mA mgPt–1 in 0.1 M KOH with 4 M methanol, significantly outperforming commercial Pt/C (446 mA mgPt–1). The transfer of electrons from Mn3O4 to Pt was confirmed through X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), and magnetic hysteresis loop analysis. Experimental and computational studies elucidate the nucleation mechanism of electron-enriched Pt, the source of active species (Pt–OH) for methanol oxidation, and the role of high-valence Mn. Furthermore, the spontaneous methanol decomposition on Pt/Mn3O4 and the corresponding active sites of dehydrogenation and CO oxidation were identified. Interference-free experiments revealed the deactivation mechanism of Pt/Mn3O4, underscoring the pivotal role of CO32– in the alkaline MOR.
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