Hierarchical trimetallic layered double hydroxide nanosheets derived from 2D metal-organic frameworks for enhanced oxygen evolution reaction

• Published in: Applied catalysis. B, Environmental Vol. 264; p. 118532
• Main Authors: Zhang, Wen-Da, Yu, Hao, Li, Tao, Hu, Qing-Tao, Gong, Yu, Zhang, Du-Ying, Liu, Yong, Fu, Qiu-Ting, Zhu, Hai-Yan, Yan, Xiaodong, Gu, Zhi-Guo
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 05-05-2020; Elsevier BV
• Subjects: 2D metal-organic frameworks; Catalysts; Conformal mapping; Durability; Electrolytes; Electron paramagnetic resonance; Fabrication; Hierarchical; Hydroxides; LDH; Metal foils; Metal-organic frameworks; Monolayer; Monolayers; Morphology; Nanosheets; Oxalic acid; Oxygen; Oxygen evolution reaction; Oxygen evolution reactions; Superhigh frequencies; Thickness; Hierarchical; LDH; Monolayer; Oxygen evolution reaction; 2D metal-organic frameworks
• ISSN: 0926-3373; 1873-3883
• DOI: 10.1016/j.apcatb.2019.118532

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Hierarchical mono-layer LDHs fabricated from oxalate MOFs as self-sacrifice template exhibit unparalleled electrocatalytic performance and stability towards OER.
•A hierarchical ultra-thin LDHs catalyst derived from 2D MOFs was fabricated.•FeCo0.5Ni0.5-LDH catalyst exhibits excellent OER activity and highly stability.•In-situ Raman spectroscopy reveals that the active site is NiOOH.•EPR spectroscopy confirms the modulating effect of Co cations.
Fabrication of monolayer LDHs nanosheets with high electrocatalytic activity and durability is still challenging. In this study, a series of hierarchical trimetallic LDHs composed of monolayer nanosheets are fabricated from oxalate metal-organic frameworks (MOFs) grown on copper foil by in-situ conformal transformation. LDHs maintain the octahedron morphology of MOFs, which is composed of ultrathin nanosheets. TEM and AFM images reveal that the thickness of the LDHs nanosheet approaches to 1 nm. These hierarchical trimetallic LDHs exhibit excellent activity and stability towards oxygen evolution reaction (OER) in alkaline electrolytes. Among them, FeCo0.5Ni0.5-LDH show the smallest overpotential of 248 mV at a current density of 10 mA cm−2 with a small Tafel slope of 38 mV dec-1, which is competitive to most reported catalysts. In-situ Raman and X-band electron paramagnetic resonance measurements reveal that the OER active sites are Ni atoms.