CO₂ Hydrogenation to Methanol on Core-Shell-Structured SiO₂-Encapsulated Cu-ZnO-In₂O₃ Nanoparticles.

Area of Science:

• Catalysis
• Materials Science
• Chemical Engineering

Background:

• Cu-ZnO catalysts for CO2 hydrogenation suffer from thermal aggregation in water.
• Developing stable and selective catalysts is crucial for methanol synthesis.

Purpose of the Study:

• To synthesize and evaluate SiO2-encapsulated Cu-ZnO-In2O3 nanoparticles for CO2 hydrogenation.
• To investigate the synergistic effects of In2O3 and SiO2 shells on catalyst performance.
• To elucidate the reaction mechanism for enhanced methanol selectivity.

Main Methods:

• Synthesis of multicore-shell Cu-ZnO-In2O3@SiO2 nanoparticles.
• Characterization of catalyst structure and properties.
• CO2 hydrogenation reaction testing.
• Density Functional Theory (DFT) calculations for mechanism elucidation.

Main Results:

• SiO2 encapsulation prevented Cu nanoparticle aggregation and enhanced catalyst stability.
• In2O3 addition decreased CO selectivity and increased methanol selectivity (>80%).
• Cu-ZnO-In2O3@SiO2 catalysts achieved 25.3% CO2 conversion and 80.1% methanol selectivity.
• DFT calculations identified the formyl pathway as favorable for methanol synthesis.

Conclusions:

• SiO2-encapsulated Cu-ZnO-In2O3 catalysts offer superior stability and selectivity for CO2 hydrogenation to methanol.
• The synergistic effects of In2O3 and SiO2 shells are key to suppressing the reverse water-gas shift reaction and enhancing methanol production.
• The formyl intermediate pathway is the preferred route for methanol synthesis over In2O3-substituted Cu surfaces.