Visible-Light-Driven Furfural Oxidation over CuO_x /Nb₂ O₅

Area of Science:

• Materials Science
• Catalysis
• Green Chemistry

Background:

• Maleic anhydride (MA) is a crucial polyester monomer derived from biomass-sourced furfural.
• Current MA production from furfural involves harsh conditions, low efficiency, and solvent corrosion.
• Developing mild and efficient methods for renewable MA production is essential.

Purpose of the Study:

• To design and evaluate a novel CuO_x/Nb₂O₅ photocatalyst for furfural oxidation.
• To achieve selective catalytic conversion of furfural to MA and 5-hydroxy-2(5H)-furanone (HF).
• To elucidate the mechanism of visible light-driven furfural activation and oxidation.

Main Methods:

• Synthesis of CuO_x nanoparticles loaded onto Nb₂O₅ support (CuO_x/Nb₂O₅).
• Photocatalytic oxidation of furfural using the synthesized catalyst under visible light irradiation.
• Analysis of reaction products and investigation of active species, including singlet oxygen (¹O₂).

Main Results:

• The CuO_x/Nb₂O₅ photocatalyst effectively absorbs visible light, activating furfural via ligand-to-metal charge transfer (LMCT).
• Singlet oxygen (¹O₂) was identified as the key active species responsible for C-C bond cleavage and CO generation.
• A combined yield of 59% for MA and HF was achieved under optimized reaction conditions.

Conclusions:

• The CuO_x/Nb₂O₅ photocatalyst provides a mild and efficient pathway for producing renewable maleic anhydride from furfural.
• This approach overcomes the limitations of traditional methods, offering a sustainable alternative.
• The study highlights the potential of photocatalysis for biomass valorization and green chemical synthesis.