Hierarchical flower-like Ni-Co layered double hydroxide nanostructures: synthesis and super performance

Three-dimensional hierarchical flower-like Ni-Co layered double hydroxide (LDH) nanostructures composed of porous nanosheets were prepared from Ni-Co precursors under optimized preparation conditions towards applications in energy storage and adsorption. Ni-Co LDHs were formed via an olation reaction and subsequent growth to nanosheet structures. It is found that suitable Ni/Co ratios for precursors resulted in Ni-Co LDHs with a large specific surface area, porous structure and expanded interlayer spacing, which contributed to the improvement in performance for electrochemistry and anionic dye adsorption. In the case of a Ni/Co molar ratio of 1, the Ni-Co LDHs as a sorbent for removing anionic dyes (acid fuchsin and Congo red) in water revealed a high adsorption rate, large adsorption capacity and good recycling performance. Using a molar ratio of Ni/Co of 0.5, the specific capacitance of the as-prepared electrode reached 3168.3 F g(-1) at a current density of 1 A g(-1) and a large capacitance retention of 90.5% after 3000 cycles at high current density. The Ni-Co LDHs possess enormous application potential as a multifunctional material for supercapacitors and dye adsorption.