Engineering Brønsted Acidic Microenvironments via Strong Metal-Support Interaction in Single-Atom Pd₁/CeO₂ for...

Area of Science:

• Catalysis
• Materials Science
• Green Chemistry

Background:

• Conventional acid-catalyzed acetalization presents challenges in catalyst recovery and environmental impact.
• Development of sustainable alternatives is crucial for industrial chemical processes.

Purpose of the Study:

• To develop an acid-free acetalization method using a supported single-atom catalyst.
• To investigate the mechanism of acid generation and catalytic activity.

Main Methods:

• Synthesis of a CeO2-supported Pd single-atom catalyst (Pd1/CeO2).
• Characterization using X-ray absorption spectroscopy (XAS) and density functional theory (DFT) calculations.
• Acetalization reaction under mild conditions with H2 activation.

Main Results:

• Pd1/CeO2 demonstrated atomic dispersion of Pd with strong metal-support interactions (SMSI).
• Catalyst facilitated heterolytic H2 activation, generating localized Hδ+ sites mimicking Brønsted acidity.
• Achieved 96.6% selectivity to cinnamal diethyl acetal with 100% conversion under mild conditions.
• Exhibited excellent stability over six catalytic cycles without performance decay.

Conclusions:

• Established a sustainable acid-free acetalization strategy by atomically engineering reactive Hδ+ sites.
• The Pd1/CeO2 catalyst offers an environmentally benign alternative to traditional acid catalysts.
• Robust Pd-O-Ce bonding and SMSI contribute to catalyst stability and prevent Pd aggregation.