Optimizing Cu 3d Bands with Nanotubular SnO₂ to Boost Their Catalytic Transfer Hydrogenation Activity

Area of Science:

• Materials Science
• Catalysis
• Nanotechnology

Background:

• Catalytic transfer hydrogenation (CTH) using copper (Cu) nanocatalysts is advantageous over high-pressure hydrogenation.
• Cu's fully occupied 3d states lead to poor active hydrogen (H*) adsorption and premature H2 release, limiting CTH efficiency.
• Optimizing Cu's electronic structure is crucial for enhancing CTH performance.

Purpose of the Study:

• To develop a Cu/SnO2 nanohybrid material to improve the electronic properties of Cu nanoparticles for CTH.
• To enhance the adsorption of active hydrogen and inhibit H2 release in CTH reactions.
• To investigate the potential of tuning non-noble metal nanocatalysts for CTH applications.

Main Methods:

• Preparation of Cu/SnO2 nanohybrids via electrospinning and hydrothermal synthesis.
• Characterization using X-ray photoelectron spectroscopy (XPS) to analyze electronic structure changes.
• Density functional theory (DFT) simulations to understand electron transfer and electronic state optimization.

Main Results:

• Electron transfer from Cu to SnO2 was confirmed, altering Cu's valence configuration to 3d10-.
• The modified electronic state enhanced active hydrogen adsorption and suppressed H2 release.
• The 15 wt% Cu/SnO2 catalyst demonstrated superior performance in 4-nitrophenol hydrogenation, with a high normalized rate constant and turnover frequency.

Conclusions:

• Cu/SnO2 nanohybrids effectively optimize Cu's electronic states, leading to enhanced catalytic activity in CTH.
• The tubular SnO2 support structure and electron-accepting properties are key to improved hydrogen adsorption.
• This approach provides a pathway for designing advanced non-noble metal nanocatalysts for efficient CTH.