Ultrahigh Stable Methanol Oxidation Enabled by a High Hydroxyl Concentration on Pt Clusters/MXene Interfaces

Area of Science:

• Materials Science
• Electrochemistry
• Catalysis

Background:

• Direct methanol fuel cells (DMFCs) require efficient anode catalysts for methanol oxidation.
• Platinum (Pt) catalysts face challenges including active site poisoning, weak support interaction, and dissolution, limiting their performance.
• MXenes, particularly Ti3C2Tx, are promising supports for anchoring metal catalysts.

Purpose of the Study:

• To develop a stable and highly active Pt-based anode catalyst for DMFCs.
• To investigate the role of 3D crumpled Ti3C2Tx MXene supports in enhancing Pt catalyst performance.
• To understand the mechanism behind the improved electrocatalytic activity and stability.

Main Methods:

• Fabrication of 3D crumpled Ti3C2Tx MXene balls with Ti vacancies using a spray-drying process.
• Anchoring of Pt clusters onto the Ti3C2Tx support to form Pt clusters/Ti3C2Tx (Ptc/Ti3C2Tx).
• Electrocatalytic evaluation of Ptc/Ti3C2Tx for methanol oxidation reaction (MOR) and other alcohol oxidations.
• In situ spectroscopy and theoretical calculations to elucidate the catalytic mechanism.

Main Results:

• The Ptc/Ti3C2Tx catalyst exhibited significantly enhanced MOR activity, including low overpotential and high tolerance to CO poisoning.
• Achieved a record mass activity of 7.32 A mgPt−1, with 42% current density retention after 3000 minutes.
• In situ studies and calculations revealed an electric field-induced repulsion at the interface accelerating COads oxidation.
• Demonstrated comparable activity and stability for ethanol, ethylene glycol, and glycerol oxidation reactions.

Conclusions:

• 3D crumpled Ti3C2Tx MXene balls with Ti vacancies provide an effective platform for Pt catalyst confinement, overcoming performance limitations.
• The Ptc/Ti3C2Tx catalyst offers superior electrocatalytic performance and stability for MOR and other alcohol oxidation reactions.
• This work presents a promising strategy for designing advanced catalysts for fuel cells and beyond.