Conventional water electrolyzers produce H2 and O2 simultaneously, such that additional gas separation steps are needed to prevent H2/O2 mixing. The sluggish anodic O2 evolution reaction (OER) always results in low overall energy conversion efficiency and the product of OER, O2, is not of significant value. In addition, the potential formation of reactive oxygen species (ROS) may lead to degradation of cell membranes and thus premature device failure. In this talk, I will present a general concept of integrating oxidative organic upgrading reactions with decoupled H2 generation from water splitting. Five representative organic substrates, ethanol, benzyl alcohol, furfural, furfuryl alcohol, and 5-hydroxymethylfurfural (HMF), were selected for oxidative upgrading catalyzed by a hierarchically porous Ni3S2/Ni foam bifunctional electrocatalyst (Ni3S2/NF). All the five organics can be oxidized to value-added liquid products at much lower overpotentials than that of OER. When utilized as electrocatalysts for both cathode and anode, Ni3S2/NF demonstrated outstanding durability and nearly unity Faradaic efficiencies for both H2 and organic upgrading. Overall, such an integrating strategy of organic oxidation and H2 evolution via earth-abundant electrocatalysts not only avoids the generation of explosive H2/O2 mixture and ROS, but also yields products of high value at both electrodes with lower voltage input, maximizing the energy conversion efficiency.

General strategy for electrocatalytic hydrogen production integrated with oxidative organic upgrading

253rd National Meeting (2017)

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