Background: Photoelectrochemical cells (PECs) use solar energy to produce fuels much as nature does through photosynthesis. In a typical PEC fuels are formed by reduction reactions at the cathode. For example water can be reduced to hydrogen gas (H2) or CO2 can be reduced to methanol and methane. To complete the circuit a reaction has to take place at the anode typically water oxidation. Technology Description: However water oxidation is slow and its product O2 is not very valuable. Identifying a more useful anode reaction would improve the overall efficiency and utility of PECs. Several efforts have focused on a chemical called HMF (5-hydroxymethylfurfural) commonly derived from biomass sugar. HMF is of great interest because it can be converted to several industrially important molecules. UW–Madison researchers have developed a new method using solar cells to electrochemically oxidize HMF to highly prized furan compounds specifically FDCA (25-furandicarboxylic acid) and DFF (25-diformylfuran). These important compounds are used to produce polymer materials pharmaceuticals antifungal agents organic conductors and much more. The reaction takes place at ambient temperature and pressure using a TEMPO mediator. Unlike previous methods the process does not require a precious metal catalyst. Applications: Production of FDCA and DFF – important building block molecules used to make a variety of materials and chemicals
1) Practical and environmentally friendly 2) High yield 3) No expensive catalyst electrodes 4) Works at ambient temperature and pressure 5) Lower pH solutions stable conditions 6) Boosts the efficiency and utility of PECs