In situ electrochemical activation of Co(OH)(2)@Ni(OH)(2) heterostructures for efficient ethanol electrooxidation reforming and innovative zinc-ethanol-air batteries

The slow kinetics of the oxygen evolution reaction (OER) has seriously hindered the development of electrical water splitting and rechargeable metal-air batteries. The ethanol oxidation reaction (EOR) to replace the OER is a promising strategy to solve this problem. Herein, we report the synthesis of Co(OH)(2)@Ni(OH)(2) heterostructures using a metal-organic framework precursor in a one-pot hydrothermal method. The catalyst showed great EOR catalytic activity (j(10) = 1.30 V) and high stability (over 100 h @ 50 mA cm(-2)). The catalytic reaction converts ethanol into acetate through 4e(-) oxidation with 97.9% faradaic efficiency. The high performance was ascribed to the double hydroxide heterostructure further processed by the electrochemical activation. In situ Raman spectra and DFT calculations identified Ni (NiOOH) as the key active sites for the EOR. Hybrid water electrolysis and zinc-ethanol-air batteries were designed based on the innovative idea of the EOR replacing the OER. The advantages of this design were proved by the 200 mV reduction in the total potential of water splitting and 300 mV reduction in the battery charging voltage, at the same time realizing the direct utilization of biomass energy.