Electrochemical Partial Reforming of Ethanol into Ethyl Acetate Using Ultrathin Co₃O₄ Nanosheets as a Highly Selective Anode Catalyst

Abstract

Electrochemical partial reforming of organics provides an alternative strategy to produce valuable organic compounds while generating H2 under mild conditions. In this work, highly selective electrochemical reforming of ethanol into ethyl acetate is successfully achieved by using ultrathin Co3O4 nanosheets with exposed (111) facets as an anode catalyst. Those nanosheets were synthesized by a one-pot, templateless hydrothermal method with the use of ammonia. NH3 was demonstrated critical to the overall formation of ultrathin Co3O4 nanosheets. With abundant active sites on Co3O4 (111), the as-synthesized ultrathin Co3O4 nanosheets exhibited enhanced electrocatalytic activities toward water and ethanol oxidations in alkaline media. More importantly, over the Co3O4 nanosheets, the electrooxidation from ethanol to ethyl acetate was so selective that no other oxidation products were yielded. With such a high selectivity, an electrolyzer cell using Co3O4 nanosheets as the anode electrocatalyst and Ni–Mo nanopowders as the cathode electrocatalyst has been successfully built for ethanol reforming. The electrolyzer cell was readily driven by a 1.5 V battery to achieve the effective production of both H2 and ethyl acetate. After the bulk electrolysis, about 95% of ethanol was electrochemically reformed into ethyl acetate. This work opens up new opportunities in designing a material system for building unique devices to generate both hydrogen and high-value organics at room temperature by utilizing electric energy from renewable sources.

Ultrathin Ni(0)‐Embedded Ni(OH)2 Heterostructured Nanosheets with Enhanced Electrochemical Overall Water Splitting

“…As illustrated in Figure S12 (Supporting Information), the heterostructured Ni/Ni(OH) 2 nanosheets displayed a smaller charge‐transfer resistance of 33.7 Ω than Ni (48.2 Ω) and Ni(OH) 2 nanosheets (122.3 Ω). The small charge‐transfer resistance of the heterostructured nanosheets indicates their superior charge transport kinetics during electrocatalysis …”

Recent Advances in Electrochemical Hydrogen Production from Water Assisted by Alternative Oxidation Reactions

“…[28] Moreover, oxidation of alcohols could potentially afford aldehyde and/or carboxylic acid products. [39][40] Thus, the use of suitable alcohols, especially biomass-derived alcohols, as anodic feedstock chemicals for coupling with the HER could not only reduce the large overpotentials and energy consumption in water electrolysis, but also potentially produce value-added chemicals. [41][42][43][44][45][46][47][48] In 2014, Vizza and co-workers demonstrated the feasibility of replacing the OER with alcohol oxidation to produce H 2 with lower required overpotentials by employing Pd nanoparticles deposited on three-dimensional nanostructured TiO 2 nanotube arrays (Pd/TNTA-wed) as the anodic electrode.…”

Prospects of Value‐Added Chemicals and Hydrogen via Electrolysis

“…Recently, the generation of hydrogen assisted by alcohol electrooxidation was possible at lower voltages compared to water electrolysis and the concept was described as “electrochemical reforming” or “chemical‐assisted HER” . Full conversion of ethanol to CO 2 can occur, but also more complex compounds like ethyl acetate were reported as oxidation products with 95 % yield and a 98 % FE on Co 2 O 3 at 1.44 V …”