Ultrathin two-dimensional Ni–MOF with high-valence oxidation states as high-performance electrocatalytic catalysts for benzyl-alcohol oxidation [具有高价氧化态的超薄二维Ni–MOF高性能电催化剂用于苯甲醇氧化反应]

作者：Yuan M.; Li Y.; Sun Z.; Sun G.^*

来源：Scientia Sinica Chimica, 2022, 52(6): 913-922.

DOI：10.1360/SSC-2021-0262

• benzyl alcohol oxidation
• electrocatalysts
• high-valence oxidation state
• two-dimensional metal-organic frameworks
• ultrathin two-dimensional structure

Ultrathin two-dimensional metal-organic frameworks (2D MOFs) have large specific surface area and open catalytically-active centers, which have potential applications in electrocatalytic reactions. This work reports the ultrathin 2D Ni–MOF nanosheet arrays with open sites prepared by a mild solvothermal method and their applications in electrocatalytic benzyl-alcohol oxidation (EBO). As a high-performance EBO electrocatalyst, the 2D Ni–MOF shows low overpotential and superior durability. It only needs a potential of about 1.50 V (vs. reversible hydrogen electrode (RHE)) to reach 250 mA cm?2, and the oxidation efficiency is more than 85%. Compared with the 2D Ni(OH)2 nanosheet arrays with the same ultrathin structure, the Ni–MOF exhibits good activity; its reaction overpotential is reduced by nearly 35 mV (@50 mA cm?2) and it has faster reaction kinetics. When benzyl alcohol oxidation is carried out at the same constant potential, the Ni–MOF has a higher response current. After continuous electrolysis for 20,000 s, the current density of 25 mA cm?2 can be retained, which is nearly twice as much as that of the Ni(OH)2 nanosheets. It is shown that Ni in the Ni–MOF nanosheets has a higher oxidation state and is easier to be converted to NiOOH in EBO reactions, so that it can effectively catalyze the electrooxidation reaction of benzyl alcohol at a lower potential. This result will provide a new perspective for the further design of electrocatalysts with high performances for EBO reactions.