Autocatalysis through the Generation of Water during Methanol Oxidation over a Titania-Supported Platinum Catalyst

Methanol may play a major role in a hydrogen economyby servingas one of the highest energy density compounds available; however,the precise reaction pathways for methanol oxidation catalysts haveyet to be fully elucidated. Herein, a combination of packed-bed reactorstudies and high-vacuum surface science techniques was used to elucidatethe reaction mechanism of methanol oxidation over a Pt/TiO2 catalyst. The reactor studies highlight that methyl formate is producedunder mild reaction conditions, and full combustion to CO2 is achieved at elevated catalyst temperatures. The surface scienceexperiments show that the production of CO2 proceeds througha surface-bound formate intermediate via multipleproton-coupled electron-transfer steps. Importantly, we also findthat the water produced upon initial methanol adsorption plays a keyrole in unlocking the oxidative chemistry of this Pt-based material.These results provide valuable insight into potential modificationsthat could preferentially direct catalyst activity toward partialor full oxidation, thereby unlocking methods for producing valuablecommodity chemicals.