Enhanced CO oxidation by reversible structural variation of supported Ag nanoparticle catalyst from single to twin by CO treatment

Twinned structure of metal nanoparticles can strongly affect catalysis because of its unique atomic alignment and bond strain in metal nanoparticles. Here, the twin and single crystal structures of supported Ag nanoparticles are controlled reversibly by gas treatment. The single crystal Ag nanoparticles were formed in Ag/Al2O3 by H2 treatment, and subsequent CO gas treatment changed the Ag particle structure to twin. The change in the Ag particle structure from single to twin caused enhancement of CO oxidation activity. In addition, the catalytic activity was reversibly changed from low to high by applying H2 and CO gas treatment to Ag/Al2O3. The kinetic analysis for CO oxidation revealed that the twin Ag nanoparticles have stronger CO adsorption energy than the single crystal ones, which is responsible for the enhanced CO oxidation activity of twin Ag nanoparticles.

Automated summary

The twinned structure of metal nanoparticles can be reversibly controlled by gas treatment, which strongly affects catalysis due to the unique atomic alignment and bond strain in metal nanoparticles. In this study, the structure of supported Ag nanoparticles on Ag/Al2O3 was changed from single crystal to twin structure by subsequent CO gas treatment after H2 treatment. This change in structure enhanced the CO oxidation activity, and the catalytic activity could be reversibly changed by applying H2 and CO gas treatment.