Cu/TiO₂ Derived from Cu-Doped MIL-125 for Enhanced Photocatalytic CO₂-to-CH₄ Conversion

Area of Science:

• Materials Science
• Catalysis
• Renewable Energy

Background:

• Photocatalytic CO2 reduction to methane is a key strategy for solar fuel production.
• Challenges include poor charge separation, CO2 activation, and multi-electron transfer kinetics.

Purpose of the Study:

• To develop efficient Cu/TiO2 photocatalysts for CO2 reduction.
• To investigate the effect of calcination temperature on catalyst performance.

Main Methods:

• Synthesis of Cu-modified defective MIL-125(Ti) precursor (Cu-MIL-125).
• Temperature-controlled calcination to produce Cu/TiO2.
• Characterization of structural, chemical, and electronic properties.
• Evaluation of photocatalytic CO2 reduction to CH4.

Main Results:

• Cu/TiO2 catalysts were successfully synthesized, with properties dependent on calcination temperature.
• The optimal catalyst (450 Cu/TiO2) achieved a CH4 formation rate of 15.90 μmol g-1 h-1 (9.8-fold enhancement).
• High CH4 selectivity (93.05%) was observed, confirmed by isotope labeling and in situ spectroscopy.

Conclusions:

• Calcination temperature critically influences Cu/TiO2 structure and photocatalytic activity.
• Metal-organic framework-derived Cu/TiO2 shows promise for efficient solar fuel production.
• This study provides a practical route for designing advanced photocatalysts.