Pt-Cu@Bi₂MoO₆/TiO₂ Photocatalyst for CO₂ Reduction.

Area of Science:

• Materials Science
• Photocatalysis
• Environmental Chemistry

Background:

• Developing efficient photocatalysts for CO₂ reduction is crucial for mitigating climate change.
• Heterojunctions offer enhanced charge separation and light absorption properties compared to single components.
• Bismuth molybdate (Bi₂MoO₆) and titanium dioxide (TiO₂) are promising semiconductor materials for photocatalysis.

Purpose of the Study:

• To construct and characterize Bi₂MoO₆/TiO₂ heterojunction photocatalysts.
• To investigate the photocatalytic activity of these composites for CO₂ reduction.
• To optimize the composition and noble metal decoration for enhanced performance.

Main Methods:

• Solvothermal synthesis of Bi₂MoO₆ nanosheets on TiO₂ nanobelts.
• Decoration of the composite surface with copper (Cu) and/or platinum (Pt) nanoparticles.
• Characterization using XRD, FESEM, EDX, N₂-physisorption, Raman, TPD-CO₂, DRS, and PL analysis.
• Evaluation of photocatalytic CO₂ reduction activity under UV-visible light irradiation.

Main Results:

• The Bi₂MoO₆/TiO₂ composites exhibited significantly enhanced photocatalytic activity compared to pure Bi₂MoO₆ and TiO₂.
• The heterojunction formation improved CO₂ adsorption capacity and suppressed charge recombination.
• The Bi₂MoO₆/TiO₂ composite with a 1/4 molar ratio (BMT4) showed optimal performance, yielding 36.4 μmol/g_cat of CO₂ reduction products in 8 hours.
• The Pt-Cu@BMT4 sample achieved the highest methane production (83.6 μmol/g_cat) under UV-visible light and demonstrated excellent stability over four cycles.

Conclusions:

• The Bi₂MoO₆/TiO₂ heterojunction structure effectively enhances photocatalytic CO₂ reduction.
• Noble metal decoration (Pt-Cu) further boosts the performance, particularly for methane production.
• The developed Pt-Cu@BMT4 photocatalyst shows great potential for efficient and stable CO₂ conversion.