Probing the enhanced methanol electrooxidation mechanism on platinum-metal oxide catalyst

Pt-metal oxide nanocomposites are classified as an alternative promising catalyst besides Pt-Ru nanoalloys for electrochemical methanol oxidation reaction (MOR), and yet the relevant enhancement mechanism for MOR remains largely elusive in terms of catalyst functions and reaction pathways. Herein, interface-rich Pt-SnO2 nanoflakes supported on reduced graphene oxide have been prepared and employed as a model catalyst for such a study. X-ray photoelectron spectroscopy and X-ray absorption spectroscopy measurements reveal significant electronic structure modification on Pt in contact with SnO2, concomitant with enhanced MOR. In-situ surface enhanced infrared absorption spectroscopy and on-line differential electrochemical mass spectrometry measurements indicate that the non-CO pathway is selectively enhanced on Pt-SnO2 compared to the CO pathway which prevails on Pt. DFT calculations reinforce that this electronic structure manipulation favors the non-CO reaction pathway on Pt-SnO2.