Scaled-up synthesis of defect-rich layered double hydroxide monolayers without organic species for efficient oxygen evolution reaction

The scaled-up synthesis of organic-free monolayer nanomaterials is highly desirable, especially in obtaining green energy by electrocatalysis. In this study, a method for the scaled-up synthesis of the series of monolayer layered double hydroxides (LDHs) without the addition of organic solvents is reported via the separate nucleation and aging steps process. The resulting monolayer LDHs with the thicknesses of less than 1 nm showed a narrow thickness distribution. X-ray absorption fine-structure revealed that monolayer NiFe-LDH nanosheets have a number of oxygen and metal vacancies defects. As a practical application, monolayer NiFe-LDH nanosheets containing defects showed an enhanced electro-catalytic water oxidation activity compared with that of bulk NiFe-LDH. Density functional theory calculations uncovered that excellent cat-alytic activity is attributed to vacancies defects. The proposed method is an economical and universally applicable strategy for the scaled-up production of monolayer LDHs. (C) 2020 Institute of Process Engineering, Chinese Academy of Sciences. Publishing services by Elsevier B.V. on behalf of KeAi Communi-cations Co., Ltd.