Aqueous OH-/H+ dual-ion gradient assisted electricity effective electro-organic synthesis of 2,5-furandicarboxylic acid paired with hydrogen fuel generation.

Abstract

The OH-/H+ dual-ion gradient has a hidden electromotive force of 0.82V under standard conditions; however, its non-redox nature completely prevents its direct interconversion as electrical driving force. We show by using organic molecules whose heterogeneous electron transfer is pH dependent, OH-/H+ dual-ion energy can be directly harvested as electrical driving force for performing simultaneous electro-organic synthesis and hydrogen fuel production in an electricity effective manner. To demonstrate this dual-ion gradient assisted electro-organic synthesis, 5-hydroxymethylfurfural (HMF) is chosen as the model molecule because of the immense techno commercial applications of its oxidized products. This dual-ion assisted device only required∼1V to provide a current density of 50mA/cm2 and for achieving the same rate; the traditional state-of-the-art electrolytic cell required a doubling of the applied potential. The dual-ion gradient assisted device can convert biomass-derived HMF to economically important FDCA with∼90% yield and∼87% Faradaic efficiency with simultaneous H2 fuel production at a potential as low as 1V.