Furfural electrovalorisation to hydrofuroin with near-unity faradaic efficiency on a single-atom zinc catalyst†

Electrochemical valorisation of biomass to value-added chemical feedstocks holds great potential to reduce the reliance on fossil fuels and accelerate the realisation of a sustainable future. In this work, we show that hydrofuroin, an important feedstock for sustainable aviation fuels, can be selectively produced on a zinc (Zn) single-atom catalyst via the electrochemical furfural reduction reaction (FRR). Initial theoretical results show that the weak binding capability of a zinc (Zn) single-atom active center effectively suppresses the parasitic hydrogen evolution reaction (HER) while enabling fast desorption and dimerization of furfural radicals towards hydrofuroin formation, which was proved by our experimental validation. The catalyst, obtained by depositing zinc phthalocyanine on purified multi-walled carbon nanotubes, exhibits near-unity faradaic efficiency for hydrofuroin production in a wide potential window, e.g., −0.5 to −0.8 V_RHE. The kinetic study further provides mechanistic insights into hydrofuroin formation on the single-atom site. This catalyst can be integrated into a flow cell electrolyser to achieve highly efficient furfural conversion to sustainable fuel precursors, which is beneficial for biomass electrovalorisation to value-added green products and chemicals.