Structural Dynamics and Operando Analysis of Nanostructured Oxide Electrodes for Photoelectrochemical Conversion of 5-Hydroxymethylfurfural to 2,5- Furandicarboxylic Acid

• Applicant: Dr.-Ing. Balakrishnan Munirathinam, Ph.D.
• Subject Area: Chemical and Thermal Process Engineering ; Solid State and Surface Chemistry, Material Synthesis ; Physical Chemistry of Solids and Surfaces, Material Characterisation
• Term: since 2025
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 564650072

Each year, 500 billion polyethylene terephthalate (PET) bottles are produced, requiring 1.9 kg of crude oil per kilogram of PET. The depletion of fossil fuels underscores the urgency to transition to sustainable alternatives. Polyethylene 2,5-furandicarboxylate (PEF), derived from lignocellulosic biomass, offers a renewable substitute for petroleum-based terephthalic acid. PEF boasts superior mechanical strength and gas barrier properties compared to PET, making it ideal for packaging applications. One green pathway to produce PEF involves the conversion of 5-hydroxymethylfurfural (HMF) into 2,5-furandicarboxylic acid (FDCA), a key precursor for PEF. Photo-electrocatalysis, which integrates solar and electric energy, enhances catalytic efficiency while reducing energy demands, making it an environmentally friendly approach. The photo-electrocatalytic conversion of HMF to FDCA is a promising method to advance green chemistry by replacing fossil-based feedstocks with renewable alternatives. This study investigates the photo-electrocatalytic conversion of HMF to FDCA using anodic nanostructured oxides as photoanodes. These materials - titanium oxide, iron oxide, tungsten oxide, and mixed titanium-iron oxide - will be fabricated through anodization, with and without co-catalyst nanoparticle modifications. Nanostructures, particularly nanotubes with circular morphologies, enhance light absorption, and co-catalysts with narrow bandgaps further improve photoactivity. The research will optimize anodization parameters - time, voltage, temperature, and electrolyte composition - as well as annealing conditions to achieve high-performance photoanodes. These conditions will be analyzed for their effects on morphology, crystallinity, bandgap, and photoactivity. Operando Fourier Transform Infrared (FTIR) spectroscopy and electrochemical tests will provide insights into reaction kinetics and intermediate pathways, offering a detailed understanding of the conversion mechanism. The goal is to develop advanced nanostructured hetero-catalysts for efficient HMF-to-FDCA conversion, enabling sustainable polymer production. By replacing petroleum feedstocks with renewable biomass-derived alternatives, this project aims to reduce environmental impacts and promote circular economy principles. This research supports global efforts to mitigate climate change and transition to sustainable materials.

• DFG Programme: Research Grants
• International Connection: Poland
• Cooperation Partner: Dr. Marta Michalska--Domanska