Boosted reverse water-gas shift activity via exsolved Cu and Ni in silicalite-1

Area of Science:

• Catalysis
• Materials Science
• Chemical Engineering

Background:

• The reverse water-gas shift (RWGS) reaction is crucial for converting CO2 into valuable CO.
• Developing efficient catalysts is key for sustainable CO2 utilization and chemical synthesis.
• Exsolution offers a novel approach to create highly dispersed and stable catalytic nanoparticles.

Purpose of the Study:

• To compare the RWGS catalytic performance of exsolved Cu- and Ni-encapsulated silicalite-1 (S-1) catalysts with conventionally prepared (impregnation) catalysts.
• To elucidate the structural and surface properties influencing the enhanced activity of exsolved catalysts.
• To provide insights for designing improved catalysts for efficient CO2 conversion.

Main Methods:

• Synthesis of exsolved Cu/S-1 and Ni/S-1 catalysts via a tailored exsolution process.
• Preparation of reference catalysts using standard impregnation methods.
• Characterization of catalyst structure, surface chemistry, and metal-support interactions using techniques like TEM, XRD, and XPS.
• Evaluation of catalytic performance in the RWGS reaction, measuring CO selectivity and conversion.
• Determination of activation energies for CO formation.

Main Results:

• Exsolved Cu- and Ni-encapsulated S-1 catalysts demonstrated superior RWGS activity compared to impregnated catalysts.
• Exsolution resulted in confined metal nanoparticles and altered surface chemistry, enhancing catalytic performance.
• Higher CO selectivity and significantly lower activation energies for CO formation were observed for exsolved catalysts.
• Surface and structural analyses confirmed improved metal-support interactions and unique adsorption properties in exsolved catalysts.

Conclusions:

• The exsolution method effectively produces highly active and selective catalysts for the RWGS reaction.
• Altered metal-support interactions and unique adsorption behaviors are key factors driving the enhanced RWGS activity of exsolved catalysts.
• This study provides a foundation for designing advanced catalysts for efficient CO2 utilization through controlled nanoparticle exsolution.