Why alloying with noble metals does not decrease the oxidation of platinum: a DFT-based ab initio thermo-dynamics...

Area of Science:

• Materials Science
• Physical Chemistry
• Computational Materials Science

Background:

• Platinum's nobility is compromised by corrosion in demanding technical applications.
• Platinum loss is often attributed to the formation of volatile platinum dioxide (PtO2).
• Alloying is a potential strategy to enhance platinum's stability and reduce corrosion.

Purpose of the Study:

• To investigate the bulk stability of various platinum alloys and their oxides.
• To evaluate the effectiveness of alloying in reducing platinum corrosion.
• To identify promising alloying elements for stabilizing platinum catalysts.

Main Methods:

• Utilized density functional theory (DFT) calculations.
• Employed ab initio and literature thermodynamic data.
• Developed an alloy model combining special-quasi-random structures (SQS) with interpolated thermodynamic properties and configurational entropy.

Main Results:

• Alloying generally reduces platinum oxidation but also decreases the overall alloy nobility.
• A direct relationship exists between the alloying metal's affinity for platinum and oxygen.
• Copper (Cu) was identified as a promising alloying element for platinum stabilization.

Conclusions:

• Alloying offers a viable route to mitigate platinum corrosion in technical applications.
• Copper alloying demonstrates potential for enhancing the stability of platinum catalysts, particularly in the Ostwald process.
• Further research into the trade-offs between corrosion resistance and alloy properties is warranted.