Atomic cerium modulated palladium nanoclusters exsolved ferrite catalysts for lean methane conversion

Area of Science:

• Materials Science
• Catalysis
• Chemical Engineering

Background:

• Palladium (Pd)-based catalysts are crucial for methane (CH₄) conversion, addressing environmental and industrial needs.
• Developing stable and active catalysts for lean methane oxidation remains a significant challenge.
• Traditional methods for activating catalysts often involve hydrogen (H₂), which can impact material stability.

Purpose of the Study:

• To develop a novel palladium nanocluster exsolved cerium-incorporated perovskite ferrite catalyst for lean methane oxidation.
• To investigate the efficacy of nitrogen (N₂) as an activation agent for palladium exsolution, replacing conventional H₂.
• To elucidate the role of atomically dispersed cerium (Ce) ions in catalyst performance and stability.

Main Methods:

• Synthesis of a Ce-incorporated perovskite ferrite catalyst.
• Activation of Pd nanocluster exsolution using N₂ as the activation agent.
• Characterization of catalyst properties using experimental techniques and theoretical calculations.

Main Results:

• N₂ activation successfully induced selective Pd nanocluster exsolution without compromising material robustness.
• The N₂-activated catalyst achieved a low T₅₀ (temperature for 50% conversion) of 350°C for lean methane oxidation.
• Atomic Ce incorporation facilitated Pd exsolution and lowered the C-H bond cleavage energy barrier, enhancing activity and stability.

Conclusions:

• N₂ serves as an effective and optimal activation agent for Pd exsolution in perovskite ferrite catalysts.
• Ce incorporation is vital for enhancing both the formation and performance of active Pd sites.
• This work introduces a new strategy for designing highly efficient catalytic interfaces through in situ exsolution.